Update README.md to add Gradle quick start

Since the library can be used in Gradle projects, most of developers nowadays uses Gradle as a build system, this simple PR provide the option to copy and paste the dependency quickly for new developers, some new developers are not familiar with maven pom xml

README.md

@@ -13,6 +13,8 @@ The code is compiled with target [Java 7](https://en.wikipedia.org/wiki/Java_ver
 
 ## Quickstart
 
+This library is published to Maven Central
+
 Add the dependency of the [latest version](https://github.com/patrickfav/bcrypt/releases/latest) to your `pom.xml`:
 
 ```xml
@@ -23,6 +25,12 @@ Add the dependency of the [latest version](https://github.com/patrickfav/bcrypt/
 </dependency>
 ```
 
+Or if you are using Gradle:
+
+```groovy
+implementation("at.favre.lib:bcrypt:{latest-version}")
+```
+
 A simple example:
 
 ```java