chore(ci): update actions/checkout to v6

.github/workflows/pr.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     name: Verify commit messages
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Run commitsar

.github/workflows/push.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     name: Build docker image
     steps:
-      - uses: actions/checkout@master
+      - uses: actions/checkout@v6
 
       - name: GitHub Package Registry
         uses: aevea/action-kaniko@master

.github/workflows/release.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0