title: Plugin was not found error during gradle build
body: <p>When trying to add the <a href="https://login.gradle.org/plugin/org.ajoberstar.grgit/2.3.0" rel="noreferrer">org.ajoberstar.grgit</a> plugin into my gradle build, I get the following error:</p>
  
  <pre><code>Plugin [id: 'org.ajoberstar.grgit', version: '2.3.0'] was not found in any of 
  the following sources:
  
  - Gradle Core Plugins (plugin is not in 'org.gradle' namespace)
  - Plugin Repositories (could not resolve plugin artifact 
   'org.ajoberstar.grgit:org.ajoberstar.grgit.gradle.plugin:2.3.0')
    Searched in the following repositories:
      Gradle Central Plugin Repository
  </code></pre>
  
  <p>Here is my code:</p>
  
  <pre><code>import org.ajoberstar.grgit.*
  
  buildscript {
      dependencies {
          classpath 'org.ajoberstar:grgit:2.3.0'
      }
  }
  
  plugins {
      id "org.sonarqube" version "2.6"
      id "idea"
      id "org.ajoberstar.grgit" version "2.3.0"
  }
  
  // ...
  </code></pre>
  
  <p>Any idea on how to solve this? Can I somehow manually download the plugin and put it into the cache?</p>