Upgrade: bump the actions group across 1 directory with 4 updates

Bumps the actions group with 4 updates in the / directory: [actions/checkout](https://github.com/actions/checkout), [OpenTTD/actions](https://github.com/openttd/actions), [OpenTTD/actions/.github/workflows/rw-entry-release-baseset.yml](https://github.com/openttd/actions) and [OpenTTD/actions/.github/workflows/rw-entry-testing-baseset.yml](https://github.com/openttd/actions).


Updates `actions/checkout` from 4 to 6
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v6)

Updates `OpenTTD/actions` from 5 to 6
- [Release notes](https://github.com/openttd/actions/releases)
- [Commits](OpenTTD/actions@v5...v6)

Updates `OpenTTD/actions/.github/workflows/rw-entry-release-baseset.yml` from 5 to 6
- [Release notes](https://github.com/openttd/actions/releases)
- [Commits](OpenTTD/actions@v5...v6)

Updates `OpenTTD/actions/.github/workflows/rw-entry-testing-baseset.yml` from 5 to 6
- [Release notes](https://github.com/openttd/actions/releases)
- [Commits](OpenTTD/actions@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: OpenTTD/actions
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: OpenTTD/actions/.github/workflows/rw-entry-release-baseset.yml
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: OpenTTD/actions/.github/workflows/rw-entry-testing-baseset.yml
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/commit-checker.yml

@@ -12,12 +12,12 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
       with:
         fetch-depth: 4
 
     - name: Get pull-request commits
-      uses: OpenTTD/actions/checkout-pull-request@v5
+      uses: OpenTTD/actions/checkout-pull-request@v6
 
     - name: Check commits
       uses: OpenTTD/OpenTTD-git-hooks@main

.github/workflows/release.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   release:
     name: Release
-    uses: OpenTTD/actions/.github/workflows/rw-entry-release-baseset.yml@v5
+    uses: OpenTTD/actions/.github/workflows/rw-entry-release-baseset.yml@v6
     secrets: inherit
     with:
       apt-packages: gimp grfcodec

.github/workflows/testing.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   testing:
     name: Testing
-    uses: OpenTTD/actions/.github/workflows/rw-entry-testing-baseset.yml@v5
+    uses: OpenTTD/actions/.github/workflows/rw-entry-testing-baseset.yml@v6
     with:
       apt-packages: gimp grfcodec
       name: opengfx