chore(deps): bump pip from 26.0 to 26.1 in /etc/loadtests/locust in the pip group across 1 directory

Bumps the pip group with 1 update in the /etc/loadtests/locust directory: [pip](https://github.com/pypa/pip).

Updates `pip` from 26.0 to 26.1
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a href="https://github.com/pypa/pip/blob/main/NEWS.rst">pip's changelog</a>.</em></p>
<blockquote>
<h1>26.1 (2026-04-26)</h1>
<h2>Deprecations and Removals</h2>
<ul>
<li>Drop support for Python 3.9. (<code>[#13795](pypa/pip#13795) &lt;https://github.com/pypa/pip/issues/13795&gt;</code>_)</li>
</ul>
<h2>Features</h2>
<ul>
<li>Add experimental support to read requirements from standardized pylock.toml files (<code>-r pylock.toml</code>). (<code>[#13876](pypa/pip#13876) &lt;https://github.com/pypa/pip/issues/13876&gt;</code>_)</li>
<li>Allow <code>--uploaded-prior-to</code> to accept a duration in days (e.g., <code>P3D</code> for 3 days ago). (<code>[#13674](pypa/pip#13674) &lt;https://github.com/pypa/pip/issues/13674&gt;</code>_)</li>
</ul>
<h2>Enhancements</h2>
<ul>
<li>Speed up dependency resolution when there are complex conflicts. (<code>[#13859](pypa/pip#13859) &lt;https://github.com/pypa/pip/issues/13859&gt;</code>_)</li>
<li>Reduce memory usage when resolving large dependency trees. (<code>[#13843](pypa/pip#13843) &lt;https://github.com/pypa/pip/issues/13843&gt;</code>_)</li>
<li>Emit a deprecation warning when pip imports an unexpected module after
installation of a distribution has started. (<code>[#13912](pypa/pip#13912) &lt;https://github.com/pypa/pip/issues/13912&gt;</code>_)</li>
<li>Allow URL constraints to apply to requirements with extras. (<code>[#12018](pypa/pip#12018) &lt;https://github.com/pypa/pip/issues/12018&gt;</code>_)</li>
<li>Allow unpinned requirements to use hashes from constraints. Constraints
like <code>{name}=={version} --hash=...</code> feeds into hash verification for
a corresponding requirement. (<code>[apereo#9243](pypa/pip#9243) &lt;https://github.com/pypa/pip/issues/9243&gt;</code>_)</li>
<li>Improve conflict reports that involve direct URLs. (<code>[#13932](pypa/pip#13932) &lt;https://github.com/pypa/pip/issues/13932&gt;</code>_)</li>
<li>Show all errors instead of first error for faulty <code>dependency_groups</code> definitions. (<code>[#13917](pypa/pip#13917) &lt;https://github.com/pypa/pip/issues/13917&gt;</code>_)</li>
</ul>
<h2>Bug Fixes</h2>
<ul>
<li>Fix recovery hint for missing RECORD file to use <code>--ignore-installed</code>
instead of <code>--force-reinstall</code>. (<code>[#12645](pypa/pip#12645) &lt;https://github.com/pypa/pip/issues/12645&gt;</code>_)</li>
<li>Fix misleading error message when a constraint file cannot be opened. (<code>[#13226](pypa/pip#13226) &lt;https://github.com/pypa/pip/issues/13226&gt;</code>_)</li>
<li>Show the filename rather than the full URL when downloading files from non-PyPI indexes in non-verbose mode. (<code>[#13494](pypa/pip#13494) &lt;https://github.com/pypa/pip/issues/13494&gt;</code>_)</li>
<li>Remove the adjacent <code>__pycache__</code> directory when a .py file is removed. (<code>[#13725](pypa/pip#13725) &lt;https://github.com/pypa/pip/issues/13725&gt;</code>_)</li>
<li>Force UTF-8 encoding for :pep:<code>723</code> metadata. (<code>[#13861](pypa/pip#13861) &lt;https://github.com/pypa/pip/issues/13861&gt;</code>_)</li>
<li>Minor performance improvement when filtering candidates during resolution. (<code>[#13916](pypa/pip#13916) &lt;https://github.com/pypa/pip/issues/13916&gt;</code>_)</li>
<li>Fix a hang on Windows when stdout is closed during verbose output. (<code>[#13927](pypa/pip#13927) &lt;https://github.com/pypa/pip/issues/13927&gt;</code>_)</li>
<li>Common path prefixes are determined by path segment, not character by character. (<code>[#13847](pypa/pip#13847) &lt;https://github.com/pypa/pip/issues/13847&gt;</code>_)</li>
<li>Fix installing <code>.tar.gz</code> source distributions that look like a zip file. (<code>[#13867](pypa/pip#13867) &lt;https://github.com/pypa/pip/issues/13867&gt;</code>_)</li>
</ul>
<h2>Vendored Libraries</h2>
<ul>
<li>Upgrade certifi to 2026.2.25</li>
<li>Upgrade packaging to 26.2</li>
<li>Upgrade requests to 2.33.1</li>
<li>Upgrade tomli to 2.3.1</li>
<li>Upgrade urllib3 to 2.6.3</li>
</ul>
<!-- raw HTML omitted -->
</blockquote>
<p>... (truncated)</p>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/pypa/pip/commit/90b2b3e0f7ef75c485155716d904e51654575803"><code>90b2b3e</code></a> Bump for release</li>
<li><a href="https://github.com/pypa/pip/commit/193f289a6201f801b23885297332461ac8a65b6b"><code>193f289</code></a> Update AUTHORS.txt</li>
<li><a href="https://github.com/pypa/pip/commit/63c3709071c9596d7f4676502a90a3b06f241772"><code>63c3709</code></a> Merge pull request <a href="https://redirect.github.com/pypa/pip/issues/13876">#13876</a> from sbidoul/install-from-pylock-reqs-sbi</li>
<li><a href="https://github.com/pypa/pip/commit/e5fe7023ffe74a5895571eaf57bdd2989018fbf2"><code>e5fe702</code></a> Merge pull request <a href="https://redirect.github.com/pypa/pip/issues/13949">#13949</a> from pypa/revert-13888-resolver-editable-links</li>
<li><a href="https://github.com/pypa/pip/commit/122a14a8cd3dae7b3e959641f0b45849d4b21618"><code>122a14a</code></a> Revert &quot;Allow editable installs to satisfy direct-URL dependencies (<a href="https://redirect.github.com/pypa/pip/issues/13888">#13888</a>)&quot;</li>
<li><a href="https://github.com/pypa/pip/commit/c3352524aae95ae959d4727dda5b5c65752261b3"><code>c335252</code></a> -r pylock.toml: add pip-wheel -r pylock.toml test</li>
<li><a href="https://github.com/pypa/pip/commit/ba2fc12b7f386d89e233bdfd49e7b89d1af57ad1"><code>ba2fc12</code></a> -r pylock.toml: proper error with remote pylock.toml containing directory ent...</li>
<li><a href="https://github.com/pypa/pip/commit/747c4ae88837a8bb13946fe9d1b612c162a2e3df"><code>747c4ae</code></a> Merge pull request <a href="https://redirect.github.com/pypa/pip/issues/13948">#13948</a> from ichard26/reword-news</li>
<li><a href="https://github.com/pypa/pip/commit/3517841c5e2d92e04dbef52c61a8fa967c059efa"><code>3517841</code></a> -r pylock: refine filename pylock-ness test</li>
<li><a href="https://github.com/pypa/pip/commit/2f7ad8caeed4471e63958df6cacba3a66a215588"><code>2f7ad8c</code></a> -r pylock.toml: fix crash with pip wheel and pip lock</li>
<li>Additional commits viewable in <a href="https://github.com/pypa/pip/compare/26.0...26.1">compare view</a></li>
</ul>
</details>
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Author: dependabot[bot]

etc/loadtests/locust/requirements.txt

@@ -10,7 +10,7 @@ locust==2.32.3
 MarkupSafe==3.0.2
 msgpack-python==0.5.6
 pyzmq==26.2.0
-pip==26.0
+pip==26.1
 six==1.16.0
 setuptools==78.1.1
 requests==2.33.0