fix(example): chips need unique key

[ghost]

fixes #959

[codecov-io]

Codecov Report

Merging #974 into rc0.15.0 will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           rc0.15.0     #974   +/-   ##
=========================================
  Coverage     94.13%   94.13%           
=========================================
  Files            86       86           
  Lines          3647     3647           
  Branches        578      578           
=========================================
  Hits           3433     3433           
  Misses           90       90           
  Partials        124      124

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