ci(github): add code coverage report badge

Author: Fonger

.github/workflows/test.yml

@@ -21,6 +21,7 @@ jobs:
     - run: yarn install --frozen-lockfile
     - run: yarn lint
     - run: yarn test
+    - run: yarn build
     - name: Upload coverage report to Codecov
       uses: codecov/codecov-action@v2.1.0
       with:

README.md

@@ -1,6 +1,6 @@
 # ts-transformer-optimize-const-enum
 
-[![](https://img.shields.io/npm/v/ts-transformer-optimize-const-enum.svg)](https://www.npmjs.com/package/ts-transformer-optimize-const-enum) ![CI Status](https://github.com/Fonger/ts-transformer-optimize-const-enum/actions/workflows/test.yml/badge.svg)
+[![](https://img.shields.io/npm/v/ts-transformer-optimize-const-enum.svg)](https://www.npmjs.com/package/ts-transformer-optimize-const-enum) ![CI Status](https://github.com/Fonger/ts-transformer-optimize-const-enum/actions/workflows/test.yml/badge.svg) [![codecov](https://codecov.io/gh/Fonger/ts-transformer-optimize-const-enum/branch/main/graph/badge.svg?token=CHDVP7EMNA)](https://codecov.io/gh/Fonger/ts-transformer-optimize-const-enum)
 
 A typescript transformer that convert exported const enum into object literal.