Expose release time through https://pub.dartlang.org/api

[isoos]

From @grouma on February 12, 2018 20:21

We currently expose the various versions through the API. It would also be useful to have the date and time the version was released.

Copied from original issue: dart-lang/pub-dev#979

[isoos]

AFAICT these should be modified in the pub_server project. We delegate these API calls to ShelfPubServer, and timestamp could be added probably in the following locations:

• https://github.com/dart-lang/pub_server/blob/master/lib/shelf_pubserver.dart#L282
• https://github.com/dart-lang/pub_server/blob/master/lib/shelf_pubserver.dart#L236

[isoos]

oops, closed by accident