Support adding specific package versions with {name}@{version} syntax

[shyndman]

No description provided.

[Vanethos]

May I ask where is this specified? I didn't saw it here: https://dart.dev/tools/pub/dependencies

[shyndman]

Oh, it's how you do it with npm. It's a timesaver if you want to install a specific version of something.

…

On Mon, Aug 5, 2019 at 3:18 PM Gonçalo Palma ***@***.***> wrote: May I ask where is this specified? I didn't saw it here: https://dart.dev/tools/pub/dependencies — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#10?email_source=notifications&email_token=AAAKKVUSREBLW5NFHSREWV3QDCRJ3A5CNFSM4IJN4L42YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD3TH7XQ#issuecomment-518422494>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAAKKVWTA3XLC6OAQJQKWM3QDCRJ3ANCNFSM4IJN4L4Q> .

[shyndman]

In fact, we might want to support a bunch of these:
https://docs.npmjs.com/cli/install