Bump version to 0.103.4

[djc]

Draft state to prevent merging before downstream is ready -- please review.

Proposed release notes

• Add unstable support for the post-quantum ML-DSA signature algorithms when using aws-lc-rs. Enable the aws-lc-rs-unstable feature to expose these algorithms (only works when aws-lc-rs-fips is not enabled).
• Use new UnsupportedSignatureAlgorithmContext, UnsupportedCrlSignatureAlgorithmContext, UnsupportedSignatureAlgorithmForPublicKeyContext and UnsupportedCrlSignatureAlgorithmForPublicKeyContext error variants which contain additional context about the error condition. The related contextless variants have been deprecated.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.53%. Comparing base (312d3de) to head (a9da95c).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #361   +/-   ##
=======================================
  Coverage   97.53%   97.53%           
=======================================
  Files          20       20           
  Lines        4094     4094           
=======================================
  Hits         3993     3993           
  Misses        101      101           

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[cpu]

Release notes LGTM

[djc]

• Published rustls-webpki v0.103.4 at registry crates-io
• [new tag] v/0.103.4 -> v/0.103.4
• Release notes