Convert environment variables list to a table in the README

[EpicWink]

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[codecov-commenter]

Codecov Report

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

Project coverage is 89.33%. Comparing base (fefa66d) to head (27192d7).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #70   +/-   ##
=======================================
  Coverage   89.33%   89.33%           
=======================================
  Files           3        3           
  Lines         741      741           
=======================================
  Hits          662      662           
  Misses         79       79           

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