fix pressDelay doesn't trigger close bug

[ctxhou]

This issue is caused from dependency library react-sortable-hoc.

Why need pressDelay?
When a draggable tab with close button, user clicks on close button will not trigger click action. Because the container of the button is wrapped by react-sortable-hoc and this lib will treat this click as dnd action then block the downward.
Therefore, to solve this issue is set the pressDelay props. It means if user clicks on the tab more than xx millisecond, trigger dnd or keep original action flow.

Why not use distance props?
Based on this issue, distance props is not working on mobile device.
Thus, pressDelay would be better solution.

fix #92.

[codecov-io]

Codecov Report

Merging #94 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #94   +/-   ##
=======================================
  Coverage   85.53%   85.53%           
=======================================
  Files          20       20           
  Lines         318      318           
  Branches       59       59           
=======================================
  Hits          272      272           
  Misses         37       37           
  Partials        9        9

Impacted Files	Coverage Δ
src/TabModal.js	50% <ø> (ø)	⬆️
src/DragTabList.js	100% <ø> (ø)	⬆️

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