Bump actions/checkout from 5 to 6

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]>

Author: dependabot[bot]

.github/workflows/gettext.yml

@@ -9,7 +9,7 @@ jobs:
 
     steps:
     - name: Clone repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         token: ${{ secrets.GIT_USER_TOKEN }}
 

.github/workflows/lint.yml

@@ -7,5 +7,5 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: elementary/actions/vala-lint@main

.github/workflows/main.yml

@@ -19,7 +19,7 @@ jobs:
       image: ghcr.io/elementary/docker:${{ matrix.version }}
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install Dependencies
         run: |
           apt update

.github/workflows/release.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     if: github.event.pull_request.merged == true && true == contains(join(github.event.pull_request.labels.*.name), 'Release')
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: elementary/actions/release@main
         env:
           GIT_USER_TOKEN: "${{ secrets.GIT_USER_TOKEN }}"