Supporting 'port livecheck installed'

[Blair Zajac]

I care about such ports, e.g. py37-tensorflow and py37-virtualenv, so I would have that in requested. So that appears to not directly solve the issue.

> On Aug 31, 2019, at 9:16 AM, Jeremy Lavergne <jeremy at lavergne.me> wrote:
> 
> As an alternative or workaround, would narrowing to `port livecheck requested` be useful for you?
> 
> 
> On 8/31/19 11:58 AM, Blair Zajac wrote:
>> Hi all,
>> It appears a number of ports, particularly py-* ports, use “livecheck.type none”. I find running ‘port livecheck installed’ a handy way to see if any of the ports I care about have an update, however, this doesn’t work for the py-* ones.
>> Can something be changed to support this? Would the livecheck code need to specially handle the port name when ${name} is a py??-* variant?
>> Blair
>