Bump actions/checkout from 3 to 4 (#247)

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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/docs_builder.yml

@@ -38,7 +38,7 @@ jobs:
 
     steps:
     - name: Get source code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Set up Python
       uses: actions/setup-python@v4

.github/workflows/test.yml

@@ -22,7 +22,7 @@ jobs:
       # to avoid 'race conditions' against Transifex
 
       - name: Check out repository code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - uses: actions/setup-python@v4
         with:

.github/workflows/wheel.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Get source code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Set up Python
         uses: actions/setup-python@v4