Add tests and coverage information, fix a minor click event bug

[dumptyd]

• section-click will now be emitted with the correct section object. Right now, it's emitted with the internal object which has some extra properties.
• Adds test coverage.
• Minor refactoring - fixing some comments, favoring object destructure syntax over Object.assign, etc.
• Bumps the version to 1.1.4.
• Updates the changelog.
• Adds automated checks to the repo using GH Actions.
• Add badges to the README.

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@a345495). Click here to learn what that means. The diff coverage is 100%.

@@           Coverage Diff           @@
##             master    #16   +/-   ##
=======================================
  Coverage          ?   100%           
=======================================
  Files             ?      4           
  Lines             ?    104           
  Branches          ?     23           
=======================================
  Hits              ?    104           
  Misses            ?      0           
  Partials          ?      0

Impacted Files	Coverage Δ
src/components/Donut.vue	100% <100%> (ø)
src/components/DonutSections.vue	100% <100%> (ø)

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