Add coveralls.io code coverage github-action

This uses the goveralls package to convert the coverage report to lcov
and send it to coveralls.io

.github/workflows/coverage.yml

@@ -0,0 +1,35 @@
+name: Coverage
+
+# NOTE(mhayden): Restricting branches prevents jobs from being doubled since
+# a push to a pull request triggers two events.
+on:
+  pull_request:
+    branches:
+      - "*"
+  push:
+    branches:
+      - master
+
+jobs:
+  test:
+    name: Test with Coverage
+    runs-on: ubuntu-latest
+    steps:
+    - name: Set up Go
+      uses: actions/setup-go@v1
+      with:
+        go-version: '1.13'
+    - name: Check out code
+      uses: actions/checkout@v2
+    - name: Install dependencies
+      run: |
+        go mod download
+    - name: Run Unit tests
+      run: |
+        go test -race -covermode atomic -coverprofile=profile.cov ./...
+    - 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