Bump actions/checkout from 6.0.2 to 7.0.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 6.0.2 to 7.0.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v6.0.2...9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/buildifier.yaml

@@ -25,7 +25,7 @@ jobs:
 
     steps:
       - name: Checkout Code
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7.0.0
 
       - name: Cache buildifier
         id: cache-buildifier

.github/workflows/github-actions-are-differences-found.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ${{ vars.USE_SELF_HOSTED == 'true' && 'self-hosted' || 'ubuntu-latest' }}
     steps:
       - name: Check out repository code
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7.0.0
         with:
           fetch-depth: 0
       - name: Check ok files

.github/workflows/on-push.yml

@@ -11,6 +11,6 @@ jobs:
     runs-on: ${{ vars.USE_SELF_HOSTED == 'true' && 'self-hosted' || 'ubuntu-latest' }}
     steps:
       - name: Check out repository code
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0  # v7.0.0
       - name: run security_scan_on_push
         uses: The-OpenROAD-Project/actions/security_scan_on_push@main