Ensuring apiGroups have an empty value

OPA Constraints don't work unless there's an apiGroup present
even if it's empty. This ensures that the empty apiGroup is present
if no apiGroups were specified.

#764

shared/gatekeeper-constraint.vue

@@ -147,12 +147,22 @@ export default {
   },
 
   async created() {
+    this.registerBeforeHook(this.willSave, 'willSave');
     if (!this.value.save) {
       this.$emit('input', merge(await this.createConstraint(), this.value, this.emptyDefaults));
     }
   },
 
   methods: {
+    willSave() {
+      this.value.spec.match.kinds.forEach((kind) => {
+        const apiGroups = kind.apiGroups || [];
+
+        if (apiGroups.length === 0) {
+          kind.apiGroups = ['*'];
+        }
+      });
+    },
     async createConstraint() {
       const constraint = await this.$store.dispatch('cluster/create', { type: this.templateOptions[0].value });