Fix #17941 dojox/widget/UpgradeBar is using deprecated dojo.cache and causes build to fail.

As per https://bugs.dojotoolkit.org/ticket/17941#ticket

The dojox/widget/UpgradeBar is using dojo.cache which is deprecated according to http://dojotoolkit.org/reference-guide/1.9/dojo/cache.html. 
The problem is in the following part of the file
````
templateString: cache("dojox.widget","UpgradeBar/UpgradeBar.html"),
````

This is also **causing builds to fail** because dojox/widget/UpgradeBar/UpgradeBar.html is getting required in the built layer.

The resolution is to easily replace it with dojo/text! Just like https://github.com/dojo/dojox/blob/master/widget/Wizard.js Funny how Wizard was using dojo/text! but UpgradeBar was not!

I have tested the solution with the test_UpgradeBar.html and test_UpgradeBar_markup.html files.

My CLA is on File!