Update CI to refresh apt packages before installing IRuby gem

[kojix2]

IRuby automatically installs the required libzmq3-dev package based on the platform. It uses a Rakefile with native-package-installer to handle this.

iruby/ext/Rakefile

Lines 5 to 19 in c95d162

	task :ensure_zeromq do
	begin
	require 'ffi-rzmq'
	rescue LoadError
	require 'native-package-installer'
	unless NativePackageInstaller.install(arch_linux: 'zeromq',
	debian: 'libzmq3-dev',
	freebsd: 'libzmq4',
	homebrew: 'zmq',
	macports: 'zmq',
	redhat: 'zeromq-devel')
	raise 'Failed to install ZeroMQ'
	end
	end
	end

Currently, many tests are failing because apt-get install shows a --fix-missing error. This happens when package lists are outdated.

https://github.com/SciRuby/iruby/actions/runs/13353020518

Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?

This issue is resolved by running apt update before installation.

      - name: Install IRuby gem
        run: |
          sudo apt update
          gem install pkg/*.gem

This ensures the package list is up to date and prevents installation failures.