fix: publish to plugins.gradle.org

Merge pull request #54 from timyates/patch-1

build.gradle

@@ -11,7 +11,7 @@ buildscript {
         classpath 'net.saliman:gradle-cobertura-plugin:2.3.2'
         classpath 'org.kt3k.gradle.plugin:coveralls-gradle-plugin:2.6.3'
         classpath 'com.github.ben-manes:gradle-versions-plugin:0.12.0'
-        classpath "com.gradle.publish:plugin-publish-plugin:0.9.5"
+        classpath "com.gradle.publish:plugin-publish-plugin:0.9.9"
     }
 }