Add Codecov

.github/workflows/test.yml

@@ -36,3 +36,11 @@ jobs:
       -
         name: Test
         run: npm run test
+      -
+        # https://github.com/codecov/codecov-action
+        name: Upload coverage
+        uses: codecov/codecov-action@v1
+        if: success()
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          file: ./coverage/clover.xml