Add case when matrix is ill-conditioned for generic procrustes

[FanwangM]

This is fixed by adding a small random noise, as discussed in #197.

The pinv function is implemented in
https://github.com/scipy/scipy/blob/4bd5e943cbf30efde4becea48c388faafa14e9e4/scipy/linalg/_basic.py#L1447, which replies on https://github.com/scipy/scipy/blob/4bd5e943cbf30efde4becea48c388faafa14e9e4/scipy/linalg/_decomp_svd.py#L13-L169. The implementation of pinv only checks explicitly if the tolerance values are valid.

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 4 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@cfcd508). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
procrustes/generic.py	33.33%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #210   +/-   ##
=======================================
  Coverage        ?   94.13%           
=======================================
  Files           ?       11           
  Lines           ?      801           
  Branches        ?        0           
=======================================
  Hits            ?      754           
  Misses          ?       47           
  Partials        ?        0           

Files with missing lines	Coverage Δ
procrustes/generic.py	75.00% <33.33%> (ø)