fix: Intall pip and pip-tools in upgrade script

[Jawayria]

Added pip-tools requirements file and updated the upgrade target script to check the compatibility of upgraded pip and pip-tools versions. For reference, look at this openedx/edx-repo-health#271 for new check added in edx-repo-health.

[codecov]

Codecov Report

Merging #371 (6dec32a) into master (17ad518) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #371   +/-   ##
=======================================
  Coverage   94.40%   94.40%           
=======================================
  Files          28       28           
  Lines        3004     3004           
  Branches      240      240           
=======================================
  Hits         2836     2836           
  Misses        150      150           
  Partials       18       18           

Flag	Coverage Δ
unittests	94.40% <ø> (ø)

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