version set to 3.2.1

[newville]

this will set the version number to 3.2.1.

I checked the rendering of the docs, and double-checked that tests/helpers.py will be included in the uncertainties-3.2.1.tar.gz file that would be ready to upload to PyPI.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 48.29%. Comparing base (2da3ca9) to head (86a68ec).

Files	Patch %	Lines
uncertainties/__init__.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #241   +/-   ##
=======================================
  Coverage   48.29%   48.29%           
=======================================
  Files          12       12           
  Lines        1903     1903           
=======================================
  Hits          919      919           
  Misses        984      984           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.