Add GitHub action for CI

[nalimilan]

Fixes https://github.com/JuliaLang/Statistics.jl/issues/60.

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@7a0c0d1). Click here to learn what that means.
The diff coverage is n/a.

@@           Coverage Diff            @@
##             master     #62   +/-   ##
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  Coverage          ?   0.00%           
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  Files             ?       1           
  Lines             ?     381           
  Branches          ?       0           
========================================
  Hits              ?       0           
  Misses            ?     381           
  Partials          ?       0           

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