piploc install --upgrade (probably) won't work

[pfmoore]

Just as a point of information, the --target option to pip doesn't work with --upgrade, so piploc -U won't work as expected.

Demonstration:

>py -m pip install -t xxx wheel==0.30.0
Collecting wheel==0.30.0
  Downloading https://files.pythonhosted.org/packages/0c/80/16a85b47702a1f47a63c104c91abdd0a6704ee8ae3b4ce4afc49bc39f9d9/wheel-0.30.0-py2.py3-none-any.whl (49kB)
    100% |████████████████████████████████| 51kB 731kB/s
Installing collected packages: wheel
Successfully installed wheel-0.30.0
>py -m pip install -t xxx -U wheel
Collecting wheel
  Using cached https://files.pythonhosted.org/packages/96/ba/a4702cbb6a3a485239fbe9525443446203f00771af9ac000fa3ef2788201/wheel-0.33.1-py2.py3-none-any.whl
Installing collected packages: wheel
Successfully installed wheel-0.33.1
>dir .\xxx


    Directory: C:\Work\Scratch\xxx


Mode                LastWriteTime         Length Name
----                -------------         ------ ----
d-----       01/03/2019     15:49                bin
d-----       01/03/2019     15:49                wheel
d-----       01/03/2019     15:49                wheel-0.30.0.dist-info
d-----       01/03/2019     15:49                wheel-0.33.1.dist-info