New release 2.10 for Unicode 16 support

[eschnett]

I'd like to have / create a new release 2.10 that supports Unicode 16. I'd be happy to create the release if others give the go-ahead.

(January 8 will be the feature freeze for Julia 1.12; if possible I'd like to have Unicode 16 in Julia 1.12.)

[clason]

@stevengj

(and that would close #272 as well)

[stevengj]

I've put together a candidate release PR #281, please take a look.

Once the release is tagged, there is also some rigamarole to update the gh-pages branch for the website.

[stevengj]

I'm getting some warnings that it would be good to fix:

utf8proc.c:702:28: warning: implicit conversion changes signedness: 'utf8proc_uint32_t' (aka 'unsigned int') to 'utf8proc_int32_t' (aka 'int') [-Wsign-conversion]
  702 |                 *starter = composition;
      |                          ~ ^~~~~~~~~~~
utf8proc.c:691:28: warning: comparison of integers of different signs: 'utf8proc_int32_t' (aka 'int') and 'utf8proc_uint32_t' (aka 'unsigned int') [-Wsign-compare]
  691 |           if (current_char <= max_second) {
      |               ~~~~~~~~~~~~ ^  ~~~~~~~~~~
utf8proc.c:695:32: warning: comparison of integers of different signs: 'utf8proc_int32_t' (aka 'int') and 'utf8proc_uint32_t' (aka 'unsigned int') [-Wsign-compare]
  695 |               if (current_char < second) {
      |                   ~~~~~~~~~~~~ ^ ~~~~~~
utf8proc.c:699:32: warning: comparison of integers of different signs: 'utf8proc_int32_t' (aka 'int') and 'utf8proc_uint32_t' (aka 'unsigned int') [-Wsign-compare]
  699 |               if (current_char == second) {

Update: fixed in #282