chore(deps): bump actions/checkout from 5 to 6 (#404)

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/ci.yml

@@ -4,7 +4,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - run: |
           npm ci
           npm run lint:all

.github/workflows/demo.yml

@@ -8,7 +8,7 @@ jobs:
     name: File Sync
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ./
         name: "Simple"
         with:

.github/workflows/release.yml

@@ -7,7 +7,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           token: ${{ secrets.SYNCED_GITHUB_TOKEN }}
           ref: "master"
@@ -20,7 +20,7 @@ jobs:
           git add dist/index.js
           git commit -m "chore: publish dist" || echo "nothing to commit"
           git push origin master
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: master
       - name: Test Action
@@ -34,7 +34,7 @@ jobs:
             adrianjost/files-sync-target
           GITHUB_TOKEN: ${{ secrets.SYNCED_GITHUB_TOKEN }}
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: master
       - name: Semantic Release

.github/workflows/synced-process-todo-comments.yml

@@ -11,7 +11,7 @@ jobs:
     name: Collect TODO
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           token: ${{ secrets.SYNCED_GITHUB_TOKEN }}
       - name: Collect TODO