move @types/node from devDependencies to dependencies

[aoberoi]

Summary

Fixes #514

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 #518 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #518   +/-   ##
======================================
  Coverage    79.7%   79.7%           
======================================
  Files           6       6           
  Lines         271     271           
  Branches       42      42           
======================================
  Hits          216     216           
  Misses         38      38           
  Partials       17      17

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