undo go.sum change, and use go 1.13 in git workflow

Signed-off-by: Stephanie <[email protected]>

Author: yangcao77

.github/workflows/go.yml

@@ -13,10 +13,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-    - name: Set up Go 1.x
-      uses: actions/setup-go@v2
+    - name: Setup Go environment
+      uses: actions/setup-go@v2.1.3
       with:
-        go-version: ^1.13
+        go-version: 1.13
       id: go
 
     - name: Check out code into the Go module directory