Update actions/checkout action to v4 (#105)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/codeanalysis.yaml

@@ -10,7 +10,7 @@ jobs:
     name: Code analysis...
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
         with:
           fetch-depth: 0  # Shallow clones should be disabled for a better relevancy of analysis
       - name: Set up JDK 11

.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/ghcr-io-docker-build.yaml

@@ -32,7 +32,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       # Workaround: https://github.com/docker/build-push-action/issues/461
       - name: Setup Docker buildx

.github/workflows/maven.yml

@@ -20,7 +20,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up JDK 11
       uses: actions/setup-java@v3
       with:
@@ -34,7 +34,7 @@ jobs:
     needs: build
 
     steps:
-    - uses: actions/checkout@v3 # Checkout the source
+    - uses: actions/checkout@v4 # Checkout the source
     - name: Login to DockerHub...
       run: |
         echo ${{ secrets.DOCKERHUB_PASSWORD }} | \