Update actions/checkout action to v4

.github/workflows/codeql-analysis.yml

@@ -38,7 +38,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/main.yaml

@@ -8,7 +8,7 @@ jobs:
     name: Lint report
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install tox
         run: pip install tox
       - name: Run tests using tox
@@ -18,7 +18,7 @@ jobs:
     name: Static analysis
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install tox
         run: pip install tox
       - name: Run tests using tox
@@ -28,7 +28,7 @@ jobs:
     name: Unit tests
     runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Install tox
         run: pip install tox
       - name: Run tests using tox
@@ -39,7 +39,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Setup LXD
         uses: canonical/setup-lxd@main
         with:
@@ -81,7 +81,7 @@ jobs:
     if: ${{ github.ref_name == 'main' }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install charmcraft
         run: sudo snap install charmcraft --classic
       - name: Fetch Tested Charm

.github/workflows/promote.yaml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Set target channel
         env:
           PROMOTE_FROM: ${{ github.event.inputs.promotion }}