ci: add gofmt step to github workflow

.github/workflows/build.yml → .github/workflows/ci.yml

@@ -1,4 +1,4 @@
-name: build
+name: ci
 on: [push, pull_request]
 
 jobs:
@@ -10,7 +10,8 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v2
         with:
-          go-version: '^1.16'
+          go-version: '^1.17'
+      - name: Format
+        run: go fmt .
       - name: Build
-        run: go build
-
+        run: go build .