Add instructions on creating sourcemap (#2008)
Add instructions on creating sourcemap (#2008)

* Add instructions on creating sourcemap

* Added output file path of the sourcemap

Co-authored-by: Steven Yau <c4e01c0f87a9d4bf034f0f681553ace272d52b0f@snaphcat.com>
aidinabedi/playcanvas-engine,sereepap2029/playcanvas,aidinabedi/playcanvas-engine,playcanvas/engine,MicroWorldwide/PlayCanvas,sereepap2029/playcanvas,playcanvas/engine,sereepap2029/playcanvas,MicroWorldwide/PlayCanvas