Remove project group from the Bintray package name in Gradle plugin

The group id is still used for dependency resolution, but should not be in the actual Bintray package name.

Author: bobbywarner

grails-gradle-plugin/src/main/groovy/org/grails/gradle/plugin/publishing/GrailsCentralPublishGradlePlugin.groovy

@@ -225,7 +225,7 @@ The values can also be placed in PROJECT_HOME/gradle.properties or USER_HOME/gra
             pkg {
                 repo = bintrayRepo
                 userOrg = bintrayOrg
-                name = "$project.group:$project.name"
+                name = "$project.name"
                 desc = bintrayDescription
                 websiteUrl = bintraySiteUrl
                 issueTrackerUrl = bintrayIssueTrackerUrl