feat(ui5-select): introduce required property (#2116)

Author: fifoosid

packages/main/src/Select.hbs

@@ -8,6 +8,7 @@
 	aria-labelledby="{{_id}}-label"
 	aria-describedby="{{valueStateTextId}}"
 	aria-disabled="{{isDisabled}}"
+	aria-required="{{required}}"
 	@keydown="{{_onkeydown}}"
 	@keyup="{{_onkeyup}}"
 	@focusin="{{_onfocusin}}"

packages/main/src/Select.js

@@ -145,6 +145,18 @@ const metadata = {
 			defaultValue: ValueState.None,
 		},
 
+		/**
+		 * Defines whether the <code>ui5-select</code> is required.
+		 *
+		 * @since 1.0.0-rc.9
+		 * @type {Boolean}
+		 * @defaultvalue false
+		 * @public
+		 */
+		required: {
+			type: Boolean,
+		},
+
 		_text: {
 			type: String,
 			noAttribute: true,