skia.org: Use fetch-ninja to install Ninja

Change-Id: I89985eefbefd4183b2e004509980465c1fc64298
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/740657
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
1 file changed