Update install docs for macOS

[dveeden]

To verify support for DBD::mysql on macOS I have:

• Added CI tests ( https://github.com/perl5-dbi/DBD-mysql/blob/master/.github/workflows/ci_mac.yml )
• Updated the docs (this PR)
• Done some manual tests (see below)

I've installed DBD::mysql on this host via cpanm and cpan.
As dependency I have tested with both mysql-client (8.1.0) and mysql-client@8.0 (8.0.35). Both installed via brew.

ec2-user@ip-172-31-29-149 ~ % sw_vers                                                                            
ProductName:		macOS
ProductVersion:		13.5.2
BuildVersion:		22G91
ec2-user@ip-172-31-29-149 ~ % which perl                                                                         
/usr/local/bin/perl
ec2-user@ip-172-31-29-149 ~ % perl -v                                                                            


This is perl 5, version 38, subversion 0 (v5.38.0) built for darwin-thread-multi-2level

Copyright 1987-2023, Larry Wall

Perl may be copied only under the terms of either the Artistic License or the
GNU General Public License, which may be found in the Perl 5 source kit.

Complete documentation for Perl, including FAQ lists, should be found on
this system using "man perl" or "perldoc perl".  If you have access to the
Internet, point your browser at https://www.perl.org/, the Perl Home Page.

ec2-user@ip-172-31-29-149 ~ % perl -e 'use DBD::mysql; print "This is DBD::mysql " . $DBD::mysql::VERSION . "\n"'
This is DBD::mysql 5.002

Related issues:

• Closes ld: library not found for -lSystem #347
• Closes Installation on a Mac 12.1 #341
• Closes macOS: Library not loaded: @rpath/libmysqlclient.21.dylib #337
• Closes make test fails on macOS Catalina: Library not loaded: @rpath/libmysqlclient.21.dylib #322
• Closes install DBD-mysql to macOS 10.13.x High Sierra  #298
• Closes cpan installation DBD::mysql problem on macos + problem resolution [rt.cpan.org #90303] #161

If you encounter any issues on macOS, please report the following:

• mysql_config output
• perl -v output
• sw_vers output
• build log
• uname -mp and/or machine output to identify the CPU architecture.

[JasonCarty-cnic]

I'm still encountering the issue mentioned in the issue 322. The solution added in here and what was mentioned in the earlier issue do not fix it. Is there something I can do to resolve it or debug the issue better?