Move 'husky install' from 'postinstall' to 'prepare'

[unimaginativeGitHub]

npm7 can't handle husky being in the 'postinstall' step. Husky documentation states 'husky install' should be run from the 'prepare' script.

Husky docs: https://github.com/typicode/husky

What did you implement:

Fixes:
• #191
• #176

How did you implement it:

Moved husky install from the postinstall script to the prepare script.

How can we verify it:

Attempt to make a commit, publish or install this module in a project that does not already have husky installed while using npm6 and npm 7.

[codecov]

Codecov Report

Merging #197 (1d13941) into master (e17efd7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #197   +/-   ##
=======================================
  Coverage   51.17%   51.17%           
=======================================
  Files          21       21           
  Lines         512      512           
  Branches      128      128           
=======================================
  Hits          262      262           
  Misses        250      250           

[scub]

Thanks for the submission @unimaginativeGitHub, we'll have a new release out shortly.