Update CMake version to match Swiftshader requirement

Change-Id: I5b12b19a6180e74b6517cda3f220381b0127e32b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/635882
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: James Godfrey-Kittle <jamesgk@google.com>
3 files changed