Specify "snappy" using msys2_mingw_dependencies

[johnnyshields]

On Windows (using Windows Ruby Installer) the Snappy gem fails to install because it is missing the MSYS2 "snappy" package. There is an easy fix for this which can be done with spec.metadata['msys2_mingw_dependencies'] = 'snappy' in the gemfile.

The error on Windows is below:

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    current directory: C:/ruby33/lib/ruby/gems/3.3.0/gems/snappy-0.3.0/ext
C:/ruby33/bin/ruby.exe extconf.rb
checking for pkg-config for libsnappy... not found
checking for -lsnappy... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.