devops: update actions/checkout

Author: bestlong

.github/workflows/dockerimage.yml

@@ -15,7 +15,7 @@ jobs:
         php_version: ["5.6", "7.0", "7.1", "7.2", "7.3", "7.4", "8.0", "8.1", "8.2"]
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Docker meta
         id: meta