BC: drop support for node<v20.18

[jkowalleck]

node < 18 is no longer maintained, and will EOL soon.
see https://github.com/nodejs/release#release-schedule
see https://nodejs.org/en/about/previous-releases

lets drop support for node < v20.18 (last release in active state)

idea:

• Support node versions greater equal last active release -- so that all implemented features are included, and maintenance releases are compatible
• and so on

(this might enable more up-to-date developer experience, and updates in some [dev-]dependencies)

[jkowalleck]

reminder: remove unused cases and the whole usage of npm_config_engine_strict=false
in the workflows

cyclonedx-javascript-library/.github/workflows/nodejs.yml

Lines 184 to 217 in d17c4b1

	run: |
	set -ex
	# for the purpose of testing strange setups,
	# we need to craft compatible versions by hand,
	# and might utilize `npm_config_engine_strict=false`
	dev_constraints=' npm-run-all2 c8 mocha fast-glob '
	# as long as npm cannot auto-resolve engine-constraints, we need to help here
	case "$NODE_VERSION" in
	'16')
	dev_constraints="${dev_constraints/ c8 / c8@^9 }"
	;;
	'14')
	dev_constraints="${dev_constraints/ c8 / c8@^9 }"
	dev_constraints="${dev_constraints/ npm-run-all2 / npm-run-all2@^5 }"
	;;
	'14.0.0')
	dev_constraints="${dev_constraints/ c8 / c8@^8 }"
	dev_constraints="${dev_constraints/ npm-run-all2 / npm-run-all2@^5 }"
	export npm_config_engine_strict=false
	;;
	esac
	echo "::group::install prod"
	npm_config_engine_strict=false npm i --ignore-scripts --include=optional --omit=dev --only=prod --production --loglevel=silly
	echo "::endgroup::"
	echo "::group::install dev"
	npm i --ignore-scripts --loglevel=silly --no-save $dev_constraints
	echo "::endgroup::"
	echo "::group::rebuild libxmljs2"
	## rebuild deps for which scripts were ignored, or partially installed - since "ignore-scripts" was used
	npm rebuild --loglevel=silly libxmljs2 || npm uninstall --no-save libxmljs2
	echo "::endgroup::"
	- name: fetch build artifact

[jkowalleck]

this becomes more and more needed.
some CT are no longer working - so we can not assert funationality ...
see https://github.com/CycloneDX/cyclonedx-javascript-library/actions/runs/12919156808