Update skia download link

This PR fixes the broken Skia download link in the manual required for building CanvasKit.

This is an imported pull request from
https://github.com/google/skia/pull/177

GitOrigin-RevId: 4500a513fc567eb6794d1fcc0dde56e569684e90
Change-Id: I9ad44b3c3cb812b5399c4b3d7efa020743da5b25
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/855876
Reviewed-by: Kaylee Lubick <kjlubick@google.com>
Reviewed-by: Ravi Mistry <rmistry@google.com>
1 file changed