ci: Update actions/checkout version

Author: theofidry

.github/workflows/coding-standards.yml

@@ -8,7 +8,7 @@ jobs:
         runs-on: "ubuntu-latest"
         steps:
             - name: "checkout"
-              uses: "actions/checkout@v2"
+              uses: "actions/checkout@v4"
 
             - name: "build the environment"
               run: "dev/bin/docker-compose build"

.github/workflows/static-analysis.yml

@@ -8,7 +8,7 @@ jobs:
         runs-on: "ubuntu-latest"
         steps:
             - name: "checkout"
-              uses: "actions/checkout@v2"
+              uses: "actions/checkout@v4"
 
             - name: "build the environment"
               run: "dev/bin/docker-compose build"

.github/workflows/unit-tests.yml

@@ -47,7 +47,7 @@ jobs:
 
         steps:
             - name: "checkout"
-              uses: "actions/checkout@v2"
+              uses: "actions/checkout@v4"
 
             - name: "build the PHP7 environment"
               run: "dev/bin/docker-compose build --build-arg PHP_VERSION=${{ matrix.php }} php"