Bump libgit2 1.9.4 to 1.9.7 - #105

The following openssl@3 configuration files have not been removed! If desired, remove them manually with `rm -rf`: /usr/local/etc/openssl@3 /usr/local/etc/openssl@3/cert.pem /usr/local/etc/openssl@3/certs /usr/local/etc/openssl@3/certs/.keepme /usr/local/etc/openssl@3/ct_log_list.cnf /usr/local/etc/openssl@3/ct_log_list.cnf.dist /usr/local/etc/openssl@3/misc /usr/local/etc/openssl@3/misc/CA.pl /usr/local/etc/openssl@3/misc/tsget /usr/local/etc/openssl@3/misc/tsget.pl /usr/local/etc/openssl@3/openssl.cnf /usr/local/etc/openssl@3/openssl.cnf.dist /usr/local/etc/openssl@3/private /usr/local/etc/openssl@3/private/.keepme