feat: support custom icon and clearIcon props

[arthurdenner]

What kind of change does this PR introduce?
Feature. Closes #296.

What is the current behavior?

• It's not possible to pass a custom component, we can only use values from SemanticUIReact;
• It's not possible to customize the clear icon, it always renders the close icon.

What is the new behavior?

• It's possible to pass a custom component to the icon prop;
• It's possible to pass a value from SemanticUIReact or a custom component to the clearIcon prop.

Checklist:

• Documentation
• Tests
• Ready to be merged

[vercel]

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[codecov]

Codecov Report

Merging #297 into develop will increase coverage by 0.39%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           develop     #297      +/-   ##
===========================================
+ Coverage    87.44%   87.84%   +0.39%     
===========================================
  Files           14       15       +1     
  Lines          462      477      +15     
  Branches        93       94       +1     
===========================================
+ Hits           404      419      +15     
  Misses          56       56              
  Partials         2        2              

Impacted Files	Coverage Δ
src/index.tsx	90.67% <ø> (ø)
src/components/icon.tsx	100.00% <100.00%> (ø)
src/components/input.tsx	100.00% <100.00%> (ø)

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[arthurdenner]

🎉 This PR is included in version 2.8.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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