Update canvaskit fiddle shader example

Change-Id: I6955bdd6e2e7040dfe151d43ea925d8d7e8f9498
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/270067
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Nathaniel Nifong <nifong@google.com>
1 file changed