Add coverage

.github/workflows/go.yml

@@ -12,17 +12,17 @@ jobs:
     name: Build
     runs-on: ubuntu-latest
     steps:
-
     - name: Set up Go
       uses: actions/setup-go@v2
       with:
         go-version: ^1.15
-
     - name: Check out code
       uses: actions/checkout@v2
-
     - name: Build
       run: make build
-
     - name: Test
-      run: make test
+      run: make test-with-coverage
+    - uses: codecov/codecov-action@v1
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }}
+        files: coverage.out