Deps: Bump actions/checkout from 6.0.3 to 7.0.0 in /sign-release-files in the dependencies group (#1737)

Deps: Bump actions/checkout

Bumps the dependencies group in /sign-release-files with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `actions/checkout` from 6.0.3 to 7.0.0
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@df4cb1c...9c091bb)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 7.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: dependencies
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

sign-release-files/action.yml

@@ -83,7 +83,7 @@ runs:
       shell: bash
     - name: Checkout repository
       if: steps.checkout.outputs.exists != 'true'
-      uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
+      uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
       with:
         repository: ${{ inputs.repository }}
     - name: Set up Python and pontos