FF: suppress pip version check in package manager

[mh105]

As pip version progresses, the pip package shipped with PsychoPy will soon go out of date. This PR suppresses the warning message about pip version update in the package manager to make the output more relevant/succinct.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 49.62%. Comparing base (713ea1f) to head (c2c933c).
Report is 27 commits behind head on release.

Additional details and impacted files

@@           Coverage Diff            @@
##           release    #6868   +/-   ##
========================================
  Coverage    49.62%   49.62%           
========================================
  Files          332      332           
  Lines        61201    61207    +6     
========================================
+ Hits         30373    30376    +3     
- Misses       30828    30831    +3     

Components	Coverage Δ
app	∅ <ø> (∅)
boilerplate	∅ <ø> (∅)
library	∅ <ø> (∅)
vm-safe library	∅ <ø> (∅)