Remove travis, add github actions

[noahrhodes]

close #6

[codecov-io]

Codecov Report

Merging #7 (9d84e84) into master (f281520) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master       #7   +/-   ##
=======================================
  Coverage   88.27%   88.27%           
=======================================
  Files           8        8           
  Lines         162      162           
=======================================
  Hits          143      143           
  Misses         19       19           

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