add codecov upload via tox

[rsokl]

No description provided.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@a0ebebc). Click here to learn what that means.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             master    #29   +/-   ##
=======================================
  Coverage          ?   100%           
=======================================
  Files             ?      6           
  Lines             ?    530           
  Branches          ?      0           
=======================================
  Hits              ?    530           
  Misses            ?      0           
  Partials          ?      0

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