fix(tabs): support heading with :

- Support `uib:tab-heading`

Closes #5590
Fixes #5568

Author: wesleycho

src/tabs/tabs.js

@@ -218,7 +218,8 @@ angular.module('ui.bootstrap.tabs', [])
       node.hasAttribute('x-uib-tab-heading') ||
       node.tagName.toLowerCase() === 'uib-tab-heading' ||
       node.tagName.toLowerCase() === 'data-uib-tab-heading' ||
-      node.tagName.toLowerCase() === 'x-uib-tab-heading'
+      node.tagName.toLowerCase() === 'x-uib-tab-heading' ||
+      node.tagName.toLowerCase() === 'uib:tab-heading'
     );
   }
 });