Bump actions/checkout from 5 to 6 (#106)

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

Author: dependabot[bot]

.github/workflows/distribution.yml

@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
 

.github/workflows/main.yml

@@ -23,7 +23,7 @@ jobs:
         os: [ubuntu-latest, macos-13]
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v6
         with:
@@ -37,7 +37,7 @@ jobs:
           echo "LEGEND_METADATA_TESTDIR=$GITHUB_WORKSPACE/legend-metadata" >> $GITHUB_ENV
       - name: Clone legend-metadata
         if: github.event.pull_request.head.repo.fork == false
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: legend-exp/legend-metadata
           fetch-depth: 0
@@ -58,7 +58,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 2
       - uses: actions/setup-python@v6
@@ -73,7 +73,7 @@ jobs:
           echo "LEGEND_METADATA_TESTDIR=$GITHUB_WORKSPACE/legend-metadata" >> $GITHUB_ENV
       - name: Clone legend-metadata
         if: github.event.pull_request.head.repo.fork == false
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: legend-exp/legend-metadata
           fetch-depth: 0
@@ -98,7 +98,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - uses: actions/setup-python@v6