Update README.ja.md

Author: technote-space

README.ja.md

@@ -3,7 +3,7 @@
 [![npm version](https://badge.fury.io/js/jquery.marker-animation.svg)](https://badge.fury.io/js/jquery.marker-animation)
 [![Build Status](https://github.com/technote-space/jquery.marker-animation/workflows/Build/badge.svg)](https://github.com/technote-space/jquery.marker-animation/actions)
 [![Build Status](https://travis-ci.com/technote-space/jquery.marker-animation.svg?branch=master)](https://travis-ci.com/technote-space/jquery.marker-animation)
-[![Coverage Status](https://coveralls.io/repos/github/technote-space/jquery.marker-animation/badge.svg?branch=master)](https://coveralls.io/github/technote-space/jquery.marker-animation?branch=master)
+[![codecov](https://codecov.io/gh/technote-space/jquery.marker-animation/branch/master/graph/badge.svg)](https://codecov.io/gh/technote-space/jquery.marker-animation)
 [![CodeFactor](https://www.codefactor.io/repository/github/technote-space/jquery.marker-animation/badge)](https://www.codefactor.io/repository/github/technote-space/jquery.marker-animation)
 [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://github.com/technote-space/jquery.marker-animation/blob/master/LICENSE)
 
@@ -144,4 +144,4 @@ $('.marker-animation').markerAnimation({
 * 太文字ではない
 * ２秒遅れてアニメーション開始
 
-が設定されます。
+が設定されます。