pygit2 1.15.0

[BrewTestBot]

Created by brew bump

---

Created with brew bump-formula-pr.

[chenrui333]

    gcc-11 -Wsign-compare -DNDEBUG -g -O3 -Wall -fPIC -I/usr/local/include -I/home/linuxbrew/.linuxbrew/opt/python@3.11/include/python3.11 -c /tmp/pygit2-20240518-7901-4sfn4x/pygit2-1.15.0/src/blob.c -o build/temp.linux-x86_64-cpython-311/tmp/pygit2-20240518-7901-4sfn4x/pygit2-1.15.0/src/blob.o
    /tmp/pygit2-20240518-7901-4sfn4x/pygit2-1.15.0/src/blob.c:31:10: fatal error: git2/sys/errors.h: No such file or directory
       31 | #include <git2/sys/errors.h>
          |          ^~~~~~~~~~~~~~~~~~~
    compilation terminated.

probably relates to #166767