Update main.yml

Update image

Author: rootsongjc

.github/workflows/main.yml

@@ -2,10 +2,10 @@ name: build-and-deploy
 on: push
 jobs:
   deploy:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-20.04
     steps:
       - name: Git checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
       - name: Build
         run: make build
       - name: Deploy