build(deps): 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/build_and_publish.yml

@@ -20,7 +20,7 @@ jobs:
     outputs:
       new_version: ${{ steps.tag.outputs.new_version }} # no prefix, may be `undefined`
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0 # all history
       - id: tag
@@ -35,7 +35,7 @@ jobs:
     needs: tag-new-version
     if: needs.tag-new-version.outputs.new_version
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: extractions/setup-just@e33e0265a09d6d736e2ee1e0eb685ef1de4669ff # v3.0.0
       - name: Set VERSION environment variable
         run: echo VERSION=${{ needs.tag-new-version.outputs.new_version }} >> $GITHUB_ENV

.github/workflows/main.yml

@@ -8,7 +8,7 @@ jobs:
   check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: "3.10"
@@ -21,7 +21,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-python@v6
         with:
           python-version: "3.10"
@@ -34,7 +34,7 @@ jobs:
   lint-dockerfile:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: hadolint/hadolint-action@2332a7b74a6de0dda2e2221d575162eba76ba5e5 # v3.3.0
         with:
           failure-threshold: error

.github/workflows/update-dependencies.yml

@@ -9,7 +9,7 @@ jobs:
   update-dependencies:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: "opensafely-core/setup-action@v1"
       with:
         python-version: "3.10"