title: Gradle: add plugin dependency from another plugin
body: <p>I'm creating gradle custom plugin and one of my tasks needs to be sure that another plugin applied to same project. Because it will operate on top of it. 
  I want for users of my plugin to avoid setting up an explicit dependency to another plugin - I want to do it inside my plugin. </p>
  
  <p>So, I want to have this plugin (<a href="https://plugins.gradle.org/plugin/org.hidetake.ssh" rel="noreferrer">https://plugins.gradle.org/plugin/org.hidetake.ssh</a>) applied. It's my dependency.</p>
  
  <p>The way how I create plugin - I just create a class code on groovy, put it in buildSrc\src\main\groovy and apply groovy plugin in project. So my custom plugin is visible to gradle on build phase. It works, I have few other plugins done this way for same project, so it's fine for now.</p>
  
  <p>I've looked through other topics and google for same question, but I can not make this work for me. This how I apply the code:</p>
  
  <pre><code>void apply(Project project) {
  
      project.buildscript {
        repositories {
          maven {
            url "https://plugins.gradle.org/m2/"
          }
        }
        dependencies {
          classpath "org.hidetake:gradle-ssh-plugin:1.1.3"
        }
      }
  
      project.apply plugin: "org.hidetake.ssh"
      ...
  </code></pre>
  
  <p>The error message I got: <strong>Plugin with id 'org.hidetake.ssh' not found</strong>.
  I tried to do it via gradle api also using project.repositories.mavenCentral()  and project.dependencies.add and project.apply(plugin:'org.hidetake.ssh') then - doesn't work also - same error message. Tried to use long notation in project.dependencies.add("myConfig",[group:'org.hidetake', name:'gradle-ssh-plugin', version:'1.1.3']) - no result.</p>
  
  <p>Appreciate if someone can guide to the correct syntax\way to make it work.</p>