refactor: platform version logic

[erisu]

Motivation, Context & Description

• Get platform version from package.json
• Remove old VERSION file which is not used as apart of the CLI workflow.

Testing

• npm t
• create project and tested with commands:
  • cordova info
  • cordova platform
  • cordova build

Checklist

• [x] I've run the tests to see all new and existing tests pass

[codecov-commenter]

Codecov Report

Merging #1206 (4be7435) into master (30954ae) will not change coverage. The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1206   +/-   ##
=======================================
  Coverage   78.53%   78.53%           
=======================================
  Files          15       15           
  Lines        1761     1761           
=======================================
  Hits         1383     1383           
  Misses        378      378           

Impacted Files	Coverage Δ
lib/Api.js	71.76% <100.00%> (ø)
lib/create.js	95.83% <100.00%> (ø)

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