feat(PaginationItem): Expose the gallery-pagination-item component

[Tiendongle]

Description

A feature request to expose the Pagination Item render elements <li> and <button> to allow for easier styling and control.

Solution

• Added a child render prop that returns index, active, activeIndex, and item props.
• Exported <GalleryPaginationItem> component
  • Added props buttonClassname and buttonProps to pass to <button> element
  • Added prop onClick and call onClick prop in the handleClick()

Note

renderPaginationItem prop was retained and conditional is set to prevent breaking changes if the package is updated.

TODO

• Document onClick callback

Existing issue mentioned: #7

[andrewrubin]

Some tiny docs changes and I think we'll be good to go!

[andrewrubin]

Couple extra tweaks before we merge, lmk if anyone has any concerns:

• Refactored the existing renderGalleryItem callback to use a property name of index instead of i. This matches the new renderPaginationItem convention.
• Refactored all demos and documentation (existing and new) to use item.id as the key prop, as this is more in line with proper React conventions.
• Bumped the package to 3.0.0

[marlonmarcello]