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]>

Author: dependabot[bot]

.github/workflows/codeql.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v2

.github/workflows/linters.yaml

@@ -19,7 +19,7 @@ jobs:
           - pylint
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Set up Python
@@ -39,7 +39,7 @@ jobs:
 
     steps:
       - name: Check out repo
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Run flake8 for Python 3
         uses: containerbuildsystem/actions/flake8@master
@@ -50,7 +50,7 @@ jobs:
 
     steps:
       - name: Check out repo
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Run markdownlint
         uses: containerbuildsystem/actions/markdownlint@master

.github/workflows/unittests.yaml

@@ -30,7 +30,7 @@ jobs:
     runs-on: ${{ matrix.env.os }}
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
 
     - name: Set up Python ${{ matrix.env.python-version }}
       uses: actions/setup-python@v4