fix: Add defaultOpenValue support

[zombieJ]

ref ant-design/ant-design#21153

[vercel]

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[codecov]

Codecov Report

Merging #23 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #23      +/-   ##
==========================================
+ Coverage   99.19%   99.19%   +<.01%     
==========================================
  Files          39       39              
  Lines        1730     1736       +6     
  Branches      526      528       +2     
==========================================
+ Hits         1716     1722       +6     
  Misses          9        9              
  Partials        5        5

Impacted Files	Coverage Δ
src/PanelContext.tsx	100% <ø> (ø)	⬆️
src/PickerPanel.tsx	100% <100%> (ø)	⬆️
src/Picker.tsx	99.07% <100%> (+0.01%)	⬆️

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[kpaxqin]

picker : 'time' 写错了吧？

文档里里 date | week | month | quarter | year

下面代码给的默认值是 picker = 'date'

而且picker应该是optional的。这里导致了一个issue:
ant-design/ant-design#22955