rm Ruby 2.4 support to address rexml CVE #1107

	name: Main
	on:
	pull_request:
	branches:
	- main
	push:
	branches:
	- main
	jobs:
	ci:
	name: CI
	strategy:
	fail-fast: false
	matrix:
	# Due to https://github.com/actions/runner/issues/849, we have to use
	# quotes for '3.0' -- without quotes, CI sees '3' and runs the latest.
	ruby: [2.5, 2.6, 2.7, '3.0', 3.1, 3.2, jruby, truffleruby-head]
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4

	# Conditionally configure bundler via environment variables as advised
	# * https://github.com/ruby/setup-ruby#bundle-config
	- name: Set bundler environment variables
	run: \|
	echo "BUNDLE_WITH=checks:docs" >> $GITHUB_ENV
	if: matrix.ruby == 3.2

	# Use 'bundler-cache: true' instead of actions/cache as advised:
	# * https://github.com/actions/cache/blob/main/examples.md#ruby---bundler
	- uses: ruby/setup-ruby@v1
	with:
	ruby-version: ${{ matrix.ruby }}
	bundler-cache: true

	- run: bundle exec rspec

	- uses: codecov/codecov-action@v4
	with:
	files: ./coverage/coverage.xml
	fail_ci_if_error: true # optional (default = false)
	token: ${{ secrets.CODECOV_TOKEN }}
	verbose: true # optional (default = false)
	if: matrix.ruby == 3.2

	- run: bundle exec rubocop
	if: matrix.ruby == 3.2

	- run: \|
	bundle exec yard doctest
	bundle exec dokaz
	if: matrix.ruby == 3.2

	- name: Run benchmarks on Ruby 2.7 or 3.2
	run: \|
	BUNDLE_GEMFILE=benchmarks/Gemfile bundle install --jobs 4 --retry 3
	BUNDLE_GEMFILE=benchmarks/Gemfile bundle exec ruby benchmarks/benchmarks.rb
	if: matrix.ruby == '2.7' \|\| matrix.ruby == '3.2'

Provide feedback