devel/libgit2: Update to 1.3.0

Use DISTVERSION and USE_GIT to follow Porter's Handbook more closely
Use PCRE2 by default instead of PCRE(1)
Use http-parser library from ports rather than bundled version as per recommendation in Porter's Handbook
Import patch to remove incompatible tests

Reference:
https://github.com/archlinux/svntogit-packages/blob/packages/libgit2/trunk/libgit2-1.2.0-remove_http-parse_incompatible_tests.patch (see commit history)

PR:		258484