Add coverage workflow

.github/workflows/go.yml

@@ -45,7 +45,7 @@ jobs:
       with:
         go-version: ${{ matrix.go-version }}
     - name: Checkout code
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
     - name: Run tests
       run: go test -v -race
 
@@ -58,7 +58,7 @@ jobs:
       with:
         go-version: 1.13.x
     - name: Checkout code
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
     - name: Calc coverage 
       run: |
         export PATH=$PATH:$(go env GOPATH)/bin   
@@ -71,5 +71,5 @@ jobs:
     - name: Coveralls
       uses: coverallsapp/github-action@v1.0.1
       with:
-          github-token: ${{ secrets.github_token }}
+          github-token: ${{ secrets.GITHUB_TOKEN }}
           path-to-lcov: coverage.lcov

README.md

@@ -2,6 +2,7 @@
 
 ![build](https://github.com/u2386/gron/workflows/Go/badge.svg?branch=master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/u2386/gron)](https://goreportcard.com/report/github.com/u2386/gron)
+[![Coverage Status](https://coveralls.io/repos/github/u2386/gron/badge.svg?branch=master)](https://coveralls.io/github/u2386/gron?branch=master)
 
 Gron is an elegant and simple periodic task scheduler, for human.