Add back snapshot support for groovy

Author: jdaugherty

build.gradle

@@ -63,6 +63,12 @@ allprojects {
         if(isSnapshot) {
             maven { url = 'https://repo.grails.org/grails/libs-snapshots-local' }
         }
+        if(groovyVersion && groovyVersion.endsWith('-SNAPSHOT')) {
+            maven {
+                name = 'ASF Snapshot repo'
+                url = 'https://repository.apache.org/content/repositories/snapshots'
+            }
+        }
     }
 }