Revert analyzer Dart language version to 2.12

Change-Id: I2076c6134f8da11ef78db96433241e2eea779a15
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/204700
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Samuel Rawlins <srawlins@google.com>

https://dart.googlesource.com/sdk/+/0740566438c510835b87cad99f088c7302c5ed5d
1 file changed
tree: 15fd4a1dbf9101ded3d2a27d14b70345a9968101
  1. commits.json