fix(Input): support null to reset value

[bindoon]

https://codepen.io/aboutblank/pen/JjPYrGj?editors=0010

[codecov]

Codecov Report

Merging #1003 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1003      +/-   ##
==========================================
- Coverage   91.44%   91.44%   -0.01%     
==========================================
  Files         247      247              
  Lines       14406    14405       -1     
  Branches     4558     4556       -2     
==========================================
- Hits        13174    13173       -1     
  Misses       1213     1213              
  Partials       19       19

Impacted Files	Coverage Δ
src/input/base.jsx	89.04% <100%> (-0.15%)	⬇️

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