Updates checkout action to V4 as per deprecation of V3

.github/build_artifacts_qgis.yml

@@ -19,7 +19,7 @@ jobs:
         architecture: ['x64']
         os: [windows-latest, macos-latest]
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set Python environment
       uses: actions/setup-python@v4
       with:

.github/workflows/build_linux.yml

@@ -9,7 +9,7 @@ jobs:
       HAS_SECRETS: ${{ secrets.AWS_SECRET_ACCESS_KEY != '' }}
     continue-on-error: true
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python 3.9
       uses: actions/setup-python@v4
       with:

.github/workflows/build_mac.yml

@@ -16,7 +16,7 @@ jobs:
       matrix:
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set Python environment
       uses: actions/setup-python@v4
       with:

.github/workflows/build_windows.yml

@@ -13,7 +13,7 @@ jobs:
         python-version: ['3.8', '3.9', '3.10', '3.11', '3.12']
         architecture: ['x64']
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set Python environment
       uses: actions/setup-python@v4
       with:

.github/workflows/debug_tests.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-20.04
     container: python:3.9
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip

.github/workflows/documentation.yml

@@ -15,7 +15,7 @@ jobs:
     env:
       HAS_SECRETS: ${{ secrets.AWS_SECRET_ACCESS_KEY != '' }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Python 3.9
       uses: actions/setup-python@v4
       with:

.github/workflows/test_linux_with_coverage.yml

@@ -11,7 +11,7 @@ jobs:
       matrix:
         python-version: [3.10]
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Install dependencies
       run: |
         sudo apt update

.github/workflows/unit_tests.yml

@@ -6,7 +6,7 @@ jobs:
   linting:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set Python environment
         uses: actions/setup-python@v4
         with:
@@ -36,7 +36,7 @@ jobs:
 
       max-parallel: 20
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set Python environment
       uses: actions/setup-python@v4
       with: