ci: Enable test coverage reporting (#126)

Author: xiehan

.github/workflows/push.yml

@@ -25,7 +25,7 @@ jobs:
           go-version: 1.18
       - name: Go test
         run: |
-          go test ./...
+          go test -cover ./...
 
   fmt_and_vet:
     name: "fmt and lint"