Add date to "finished" message

[mottosso]

Sometimes, deployment takes time and you aren't sitting around watching it.

rez env git pipz -- install . --prefix S:\slow\drive
Using python-3.7
Using pip-19.1.1
Reading package lists... ok - 21.68s
Discovering existing packages... ok - 1.22s
The following NEW packages will be installed:
  allzpark    1.2.21
Packages will be installed to S:\slow\drive
After this operation, 0.83 mb will be used.
Do you want to continue? [Y/n] y
(1/1) Installing allzpark-1.2.21... ok
1 installed, 0 skipped
Completed in 213.96s

That's when it'd be helpful is as part of the output there was also some indication of current time.

Completed in 213.96s at 11:42 Tuesday 12 July 2019