Run go fmt on CI (#118)

* ensure go fmt has no output

* fix go fmt line

* fix go fmt stdout/stderr

Author: yaronya

.github/workflows/ci.yml

@@ -14,5 +14,8 @@ jobs:
           go-version: 1.16 # please change also in `release.yml` and `go.mod`
       - name: Checkout code
         uses: actions/checkout@v2
+      - name: Go fmt
+        run: |
+            ! go fmt ./... | read
       - name: Go Test
         run: go test -v ./...