not work on mac m1 gnuplot

[daddygongon]

Thanks for maintaining great gem.👍 Unfortunately on my new mac m1(BigSur), numo-gnuplot doesn' t work. The error tells,

Traceback (most recent call last):
	3: from test.rb:5:in `<main>'
	2: from /Users/bob/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/numo-gnuplot-0.2.4/lib/numo/gnuplot.rb:79:in `plot'
	1: from /Users/bob/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/numo-gnuplot-0.2.4/lib/numo/gnuplot.rb:94:in `_plot_splot'
/Users/bob/.rbenv/versions/2.7.2/lib/ruby/gems/2.7.0/gems/numo-gnuplot-0.2.4/lib/numo/gnuplot.rb:307:in `run':  (Numo::GnuplotError)
qt.qpa.fonts: Populating font family aliases took 408 ms. Replace uses of missing font family "Monospace 12" with one that exists to avoid this cost.

The code is

require "numo/gnuplot"

gp = Numo::Gnuplot.new
gp.set title:"Example Plot"
gp.plot "sin(x)",w:"lines"

and the gnuplot is

	G N U P L O T
	Version 5.4 patchlevel 1    last modified 2020-12-01 

	Copyright (C) 1986-1993, 1998, 2004, 2007-2020
	Thomas Williams, Colin Kelley and many others

	gnuplot home:     http://www.gnuplot.info
	faq, bugs, etc:   type "help FAQ"
	immediate help:   type "help"  (plot window: hit 'h')

Terminal type is now 'qt'

I've search around the error related issues, but can't fix them.