bump checkout action version

.github/workflows/docker.yaml

@@ -17,7 +17,7 @@ jobs:
         steps:
 
             - name: Checkout code
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
 
             - name: Install buildx
               uses: docker/setup-buildx-action@v2

.github/workflows/lockfiles.yaml

@@ -11,7 +11,7 @@ jobs:
         steps:
 
             - name: Clone Kimai
-              uses: actions/checkout@v3
+              uses: actions/checkout@v4
               with:
                   persist-credentials: false
 

.github/workflows/testing.yaml

@@ -25,7 +25,7 @@ jobs:
         steps:
 
             -   name: Clone Kimai
-                uses: actions/checkout@v3
+                uses: actions/checkout@v4
                 with:
                     persist-credentials: false