fix workflow: Unable to process command

Author: dchaofei

.github/workflows/extra.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
 
     - name: Setup Go environment
       uses: actions/setup-go@v1