Pin using hashes rather than tags
Pin using hashes rather than tags

Related: https://github.com/flutter/flutter/issues/99797
Change-Id: Idf987b284dcd5236135e18d12a331ce95b274510
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/236040
Reviewed-by: Ryan Macnak <d738b7f001baf9789095d7dc549cff6de60b011d@google.com>
Commit-Queue: Zach Anderson <9f8b31e960a68dade71618f1ff6da6e23a1edfc9@google.com>

dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk,dart-lang/sdk