updated minimum node version to 12.13.0, updated minimum typescript t…

[stevengill]

…o 4.1

Fixes issue: #727

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

Merging #728 (a2f8453) into v3 (fd35a5c) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##               v3     #728   +/-   ##
=======================================
  Coverage   83.18%   83.18%           
=======================================
  Files           8        8           
  Lines         773      773           
  Branches      233      233           
=======================================
  Hits          643      643           
  Misses         86       86           
  Partials       44       44           

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