test: add test coverage workflow

.github/workflows/go.yml

@@ -0,0 +1,33 @@
+name: Go
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+
+  build:
+    name: Build
+    runs-on: ubuntu-latest
+    steps:
+
+    - name: Set up Go 1.x
+      uses: actions/setup-go@v2
+      with:
+        go-version: ^1.13
+      id: go
+
+    - name: Check out code into the Go module directory
+      uses: actions/checkout@v2
+
+    - name: Test
+      run: go test -covermode=count -coverprofile=profile.cov ./pkg/...
+
+    - name: Send coverage
+      env:
+        COVERALLS_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      run: |
+        GO111MODULE=off go get github.com/mattn/goveralls
+        $(go env GOPATH)/bin/goveralls -coverprofile=profile.cov -service=github