Bump actions/checkout from 6 to 7

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/DocsCleanup.yml

@@ -16,7 +16,7 @@ jobs:
       contents: write
     steps:
       - name: Checkout gh-pages branch
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
         with:
           ref: gh-pages
       - name: Delete preview and history + push changes

.github/workflows/Documentation.yml

@@ -20,7 +20,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       # # Install all required X11 and OpenGL libraries
       # # These are needed for GLMakie to work in a headless environment

.github/workflows/TestExtensions.yml

@@ -26,7 +26,7 @@ jobs:
           - "pre"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v7
 
       - name: "Setup Julia ${{ matrix.version }}"
         uses: julia-actions/setup-julia@v2