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] <support@github.com>

.github/workflows/linting.yml

@@ -11,7 +11,7 @@ jobs:
         python-version: [3.8]
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python ${{ matrix.python-version }}
       uses: actions/setup-python@v4
       with:

.github/workflows/releasing.yml

@@ -17,7 +17,7 @@ jobs:
     timeout-minutes: 10
     steps:
     - name: Checkout 🛎️
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
     - name: Set up Python 🐍
       uses: actions/setup-python@v4
       with:

.github/workflows/testing.yml

@@ -17,7 +17,7 @@ jobs:
           - {os: 'ubuntu-20.04', python-version: "3.8", requires: 'oldest'}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Python ${{ matrix.python-version }}
         uses: actions/setup-python@v4
         with: