Update to actions/checkout@v4

Author: ur5us

.github/workflows/main.yml

@@ -35,7 +35,7 @@ jobs:
           --health-timeout 5s
           --health-retries 5
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with: