chore(deps): bump actions/checkout from 5 to 6 in the ci group

Bumps the ci group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `actions/checkout` from 5 to 6
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: ci
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/check-manifest-generation-diff.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         fetch-depth: 0
     - name: Setup Go

.github/workflows/release.yaml

@@ -17,7 +17,7 @@ jobs:
       packages: 'write'
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: webfactory/[email protected]
         with:
           ssh-private-key: ${{ secrets.GIT_CHECKOUT_KEY }}

.github/workflows/test.yml

@@ -12,7 +12,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Set up Go
       uses: actions/setup-go@v6