[build][babel] let consumers polyfill

[williaster]

🏠 Internal

💥 [possibly breaking] Previously we've configured @babel/preset-env useBuiltIns to "usage" which has caused issues with core-js deps. Rather than adding a core-js dep we'll punt on polyfills to consumers.

Note:

• fixes a bug in 0.0.73 which required consumers to install core-js, now they can install whatever they want
• this doesn't apply to event-flow because it is bundled as a mini app essentially.

[codecov]

Codecov Report

Merging #155 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #155   +/-   ##
=======================================
  Coverage   80.53%   80.53%           
=======================================
  Files         109      109           
  Lines        2415     2415           
  Branches      568      568           
=======================================
  Hits         1945     1945           
  Misses        290      290           
  Partials      180      180

Impacted Files	Coverage Δ
packages/xy-chart/src/utils/brush/Brush.jsx	83.96% <ø> (ø)	⬆️

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