Added GPC Grails-Cascade-Validation plugin

Author: dauer

grails-plugins/io/github/gpc/cascade-validation.yml

@@ -0,0 +1,10 @@
+name: cascade-validation
+desc: Grails Cascade Validation plugin
+coords: io.github.gpc:cascade-validation
+owner: gpc
+vcs: https://github.com/gpc/grails-cascade-validation
+maven-repo: https://repo1.maven.org/maven2
+labels:
+  - validation
+licenses:
+  - Apache-2.0