Update to the latest package:convert
Update to the latest package:convert

Change-Id: I93ad7ae4f8bc5982c803a7951d097ad505a91526
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/204921
Auto-Submit: Nate Bosch <dc212c74d8afde9c690fdd09e74d3e5c5d5a3de0@google.com>
Commit-Queue: Gary Roumanis <d5b6b5e05b98e5bbacdd1eed49204da9b1e1f2d1@google.com>
Reviewed-by: Gary Roumanis <d5b6b5e05b98e5bbacdd1eed49204da9b1e1f2d1@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