Prefix dev, rc, and post with "." to make compatible with PEP440

[rodrigc]

Fixes #38

[codecov]

Codecov Report

Merging #62 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master      #62   +/-   ##
=======================================
  Coverage   96.86%   96.86%           
=======================================
  Files           5        5           
  Lines         733      733           
  Branches       68       68           
=======================================
  Hits          710      710           
  Misses         11       11           
  Partials       12       12           

Impacted Files	Coverage Δ
src/incremental/tests/test_version.py	100.00% <ø> (ø)
src/incremental/__init__.py	87.19% <100.00%> (ø)
src/incremental/tests/test_update.py	100.00% <100.00%> (ø)

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[wsanchez]

yup

[rodrigc]

Thanks. I don't have permissions to merge this, so can't move forward.