Add codecov configuration file and ignore setup.py and versioneer.py

[martin-springer]

• [x] Code changes are covered by tests
• [x] Code changes have been evaluated for compatibility/integration with TrendAnalysis
• [x] New functions added to __init__.py
• [x] API.rst is up to date, along with other sphinx docs pages
• [x] Example notebooks are rerun and differences in results scrutinized
• [x] Updated changelog

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 96.10%. Comparing base (6ef4a0e) to head (88ad268).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## aggregated_filters_for_trials #420 +/- ## ================================================================== + Coverage 75.52% 96.10% +20.57% ================================================================== Files 13 11 -2 Lines 2807 2206 -601 ================================================================== Hits 2120 2120 + Misses 687 86 -601 ```

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