Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/docs.yml

@@ -16,7 +16,7 @@ jobs:
     env:
       DOCS_PATH: ./docs/_build/html/
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - uses: conda-incubator/setup-miniconda@v2
@@ -66,7 +66,7 @@ jobs:
       # needs write permission to push the docs to gh-pages
       contents: write
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0
           ref: gh-pages

.github/workflows/release.yml

@@ -24,7 +24,7 @@ jobs:
       ID: ${{ steps.create_release.outputs.id }}
       VERSION: ${{ env.VERSION }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Get version (on tag)
         if: startsWith(github.ref, 'refs/tags/')
@@ -107,7 +107,7 @@ jobs:
       MICROMAMBA_VERSION: '1.4.2'
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: conda-incubator/setup-miniconda@v2
         with:
           miniforge-variant: Mambaforge
@@ -299,7 +299,7 @@ jobs:
       LIB_TO_TEST_SKIP: ''
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Download Winpython
         run: |
           Invoke-WebRequest -OutFile ${{ env.WP_EXE }} ${{ env.WP_URL }}