Release 0.21.3

[eddelbuettel]

This PR updates the package to release 0.21.3. From NEWS.md (with 'lowered' headline levels for display here):

tiledb 0.21.3

• This release of the R package builds against TileDB 2.17.4, and has also been tested against earlier releases as well as the development version (Use TileDB 2.17.4 #611)

Improvements

• Query conditioning parsing now supports factor index columns other than the standard integer type (Generalize query condition parsing to non-INT32 index columns #614)

Build and Test Systems

• The nighly valgrind run was updated to include release 2.18 (Extend nightly valgrind run to 2.18 #615)

Documentation

• The pkgdown documentation has been updated for release 0.21.2 (Updated pkgdown documentation for release 0.21.2 #613) and release 0.21.3 (Release 0.21.3 #616)

[shortcut-integration]

This pull request has been linked to Shortcut Story #36595: Release 0.21.3.