Bump actions/checkout from 5 to 6 (#346)

Bumps [actions/checkout](https://github.com/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
...

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

Author: dependabot[bot]

.github/workflows/clang-format-check.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - name: Check out stratum repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Get list of changed Files
         id: changes

.github/workflows/pipeline.yml

@@ -37,7 +37,7 @@ jobs:
 
     steps:
       - name: Clone stratum repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Mount bazel cache
         uses: actions/cache@v4
@@ -77,7 +77,7 @@ jobs:
 
     steps:
       - name: Clone stratum repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Mount bazel cache
         uses: actions/cache@v4
@@ -103,7 +103,7 @@ jobs:
 
     steps:
       - name: Clone stratum repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           path: stratum