Add envName to allow custom variable to define env

[bfricka]

Link to issue

#219

Description of changes being made

Added an envName option for those who want to override the default APP_ENV.

[codecov]

Codecov Report

Merging #220 (9190bea) into main (88d3118) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #220   +/-   ##
=======================================
  Coverage   97.95%   97.95%           
=======================================
  Files           1        1           
  Lines          49       49           
=======================================
  Hits           48       48           
  Misses          1        1           

Impacted Files	Coverage Δ
index.js	97.95% <100.00%> (ø)

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[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[bfricka]

This shouldn't be closed. It's just been ignored.