chore: show a deprecation warning for old tags (#3088)

Author: vladitasev

packages/base/hash.txt

@@ -1 +1 @@
-EpEv8ewlNPY90ULIm8etkaS9plo=
+WeIr8BhWti5PEgIpG30j/drpLD4=

packages/base/src/UI5Element.js

@@ -999,7 +999,9 @@ class UI5Element extends HTMLElement {
 
 			if (altTag && !customElements.get(altTag)) {
 				registerTag(altTag);
-				window.customElements.define(altTag, getClassCopy(this));
+				window.customElements.define(altTag, getClassCopy(this, () => {
+					console.log(`The ${altTag} tag is deprecated and will be removed in the next release, please use ${tag} instead.`); // eslint-disable-line
+				}));
 			}
 		}
 		return this;

packages/base/src/util/getClassCopy.js

@@ -1,5 +1,10 @@
-const getClassCopy = klass => {
-	return class classCopy extends klass {};
+const getClassCopy = (klass, constructorCallback) => {
+	return class classCopy extends klass {
+		constructor() {
+			super();
+			constructorCallback && constructorCallback();
+		}
+	};
 };
 
 export default getClassCopy;