Add generated files check to github actions

.github/workflows/tests.yml

@@ -23,6 +23,18 @@ jobs:
         go-version: ^1.13
       id: go
 
+    - name: Check generated files
+      run: |
+        PROTOC_ZIP=protoc-3.6.1-linux-x86_64.zip
+        curl -OL https://github.com/protocolbuffers/protobuf/releases/download/v3.6.1/$PROTOC_ZIP
+        sudo unzip -o $PROTOC_ZIP -d /usr/local bin/protoc
+        sudo unzip -o $PROTOC_ZIP -d /usr/local 'include/*'
+        sudo chmod -R o+r /usr/local/include/google/
+        rm -f $PROTOC_ZIP
+        make gen
+        git update-index --refresh
+        git diff-index --quiet HEAD
+
     - name: Build and Test
       run: make test