Remove fusion-tokens as peerDependency, promote prop-types to dependency

[derekjuber]

1. Removes fusion-tokens since it's unused now
2. Updates the pin for fusion-test-utils so we can remove fusion-tokens
3. Adds prop-types as a regular dependency as per the suggestion here: https://github.com/facebook/prop-types#how-to-depend-on-this-package

[codecov]

Codecov Report

Merging #93 into master will not change coverage.
The diff coverage is n/a.

@@         Coverage Diff          @@
##           master   #93   +/-   ##
====================================
  Coverage      48%   48%           
====================================
  Files           8     8           
  Lines         125   125           
  Branches       21    21           
====================================
  Hits           60    60           
  Misses         65    65

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[derekjuber]

!merge