feat: support RegExp in ignoredElements (#6769)

Author: raymondmuller

Diff for: src/core/vdom/patch.js

@@ -120,7 +120,14 @@ export function createPatchFunction (backend) {
         if (
           !inPre &&
           !vnode.ns &&
-          !(config.ignoredElements.length && config.ignoredElements.indexOf(tag) > -1) &&
+          !(
+            config.ignoredElements.length &&
+            config.ignoredElements.some(ignore => {
+              return ignore instanceof RegExp
+                ? ignore.test(tag)
+                : ignore === tag
+            })
+          ) &&
           config.isUnknownElement(tag)
         ) {
           warn(