chore(deps): update actions/checkout action to v6 (#181)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://github.com/actions/checkout) | action | major | `v4` → `v6` |

---

### Release Notes

<details>
<summary>actions/checkout (actions/checkout)</summary>

### [`v6`](https://github.com/actions/checkout/blob/HEAD/CHANGELOG.md#v600)

[Compare Source](actions/checkout@v5...v6)

- Persist creds to a separate file by [@&#8203;ericsciple](https://github.com/ericsciple) in [#&#8203;2286](actions/checkout#2286)
- Update README to include Node.js 24 support details and requirements by [@&#8203;salmanmkc](https://github.com/salmanmkc) in [#&#8203;2248](actions/checkout#2248)

### [`v5`](https://github.com/actions/checkout/blob/HEAD/CHANGELOG.md#v501)

[Compare Source](actions/checkout@v4...v5)

- Port v6 cleanup to v5 by [@&#8203;ericsciple](https://github.com/ericsciple) in [#&#8203;2301](actions/checkout#2301)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0MS4xNzMuMSIsInVwZGF0ZWRJblZlciI6IjQyLjcyLjAiLCJ0YXJnZXRCcmFuY2giOiJtYXN0ZXIiLCJsYWJlbHMiOltdfQ==-->

Reviewed-on: https://kubara.git.onstackit.cloud/STACKIT/kubara/pulls/181
Co-authored-by: Matthias_Huether <matthias.huether_ext@external.stackit.cloud>
Co-committed-by: Matthias_Huether <matthias.huether_ext@external.stackit.cloud>

Author: Matthias_Huether

.forgejo/workflows/docs-build-push-latest-dev.yaml

@@ -17,7 +17,7 @@ jobs:
         working-directory: ./docs
     steps:
       - name: checkout kubara repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           token: ${{ secrets.DOCS_CF_PAT }}
           fetch-depth: 0

.forgejo/workflows/docs-build-push-latest-stable.yaml

@@ -18,7 +18,7 @@ jobs:
         working-directory: ./docs
     steps:
       - name: checkout kubara repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           token: ${{ secrets.DOCS_CF_PAT }}
           fetch-depth: 0

.forgejo/workflows/pre-commit.yaml

@@ -11,7 +11,7 @@ jobs:
         password: ${{ secrets.HARBOR_REGISTRY_TOKEN }}
     steps:
       - name: checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: check python version
         run: |
           python --version

.forgejo/workflows/release.yaml

@@ -17,7 +17,7 @@ jobs:
         password: ${{ secrets.HARBOR_REGISTRY_TOKEN }}
     steps:
       - name: checkout kubara repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
           fetch-tags: true

.forgejo/workflows/renovate.yaml

@@ -10,7 +10,7 @@ jobs:
       image: catthehacker/ubuntu:runner-24.04
     steps:
       - name: checkout kubara repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
       - name: run renovatebot
         uses: renovatebot/github-action@v44.2.3
         with:

.forgejo/workflows/testsuite_01-build-generate.yaml

@@ -45,7 +45,7 @@ jobs:
         working-directory: ${{ env.CODE_PATH }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           sparse-checkout: go-binary
 
@@ -175,7 +175,7 @@ jobs:
         working-directory: ${{ env.CODE_PATH }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           sparse-checkout: go-binary
 
@@ -239,7 +239,7 @@ jobs:
       binary-size: ${{ steps.build.outputs.binary-size }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           sparse-checkout: go-binary
 
@@ -331,7 +331,7 @@ jobs:
       KUBARA_PUBLIC_LOADBALANCER_IP: "0.0.0.0"
     steps:
       - name: Checkout Test Repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           path: testRepo
           token: ${{ secrets.ARGOCD_GIT_PAT }}

.forgejo/workflows/testsuite_02-static-analysis.yaml

@@ -29,7 +29,7 @@ jobs:
 
     steps:
       - name: Checkout test repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           path: testRepo
           token: ${{ secrets.ARGOCD_GIT_PAT }}
@@ -159,7 +159,7 @@ jobs:
 
     steps:
       - name: Checkout test repo
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           path: testRepo
           token: ${{ secrets.ARGOCD_GIT_PAT }}