build: explicitly add versioning plugin

... it is unclear why it is not automatically applied by the
conventions.

Author: stempler

build.gradle

@@ -6,6 +6,7 @@ plugins {
 	id "eclipse"
 	id "maven-publish"
 	id "com.gradle.plugin-publish" version "2.1.1"
+	id 'to.wetransform.semantic-release-version' version '2.1.3'
 	id 'to.wetransform.conventions' version '3.0.0'
 }