Update CI badge to refer to GitHub Actions

.github/workflows/gradle.yml

@@ -1,7 +1,7 @@
 # This workflow will build a Java project with Gradle and cache/restore any dependencies to improve the workflow execution time
 # For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-gradle
 
-name: Java CI with Gradle
+name: Build
 
 on: [push, pull_request]
 

README.md

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-Mirage-SQL [![Build Status](https://travis-ci.org/mirage-sql/mirage.svg?branch=master)](https://travis-ci.org/mirage-sql/mirage) [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.miragesql/miragesql/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.miragesql/miragesql) [![Join the chat at https://gitter.im/mirage-sql/mirage-sql](https://badges.gitter.im/mirage-sql/mirage-sql.svg)](https://gitter.im/mirage-sql/mirage-sql?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+Mirage-SQL [![Build](https://github.com/mirage-sql/mirage/actions/workflows/gradle.yml/badge.svg)](https://github.com/mirage-sql/mirage/actions/workflows/gradle.yml) [![Maven Central](https://maven-badges.herokuapp.com/maven-central/com.miragesql/miragesql/badge.svg)](https://maven-badges.herokuapp.com/maven-central/com.miragesql/miragesql) [![Join the chat at https://gitter.im/mirage-sql/mirage-sql](https://badges.gitter.im/mirage-sql/mirage-sql.svg)](https://gitter.im/mirage-sql/mirage-sql?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 ======
 
 **`Mirage-SQL`** is an easy and powerful SQL-centric database access library for Java (or JVM based languages) which provides dynamic SQL templates in plain SQL files.