Drop Node.js 18 support

[eucyt]

Resolved #1259

TODO

• Remove CI by Node.js 18 from Status checks that are required.

[eucyt]

I've confrimed npm run apidocs and npm run docs:build by Node.js 24

[Yang-33]

They are already tested.

line-bot-sdk-nodejs/.github/workflows/test.yml

Lines 41 to 55 in ee85d1a

	- name: Generate code
	run: |
	python3 generate-code.py
	- name: Test Project
	run: export NODE_OPTIONS=--max-old-space-size=6144; npm test
	- name: Test building apidocs
	run: export NODE_OPTIONS=--openssl-legacy-provider; npm run apidocs
	- name: Test building docs
	run: export NODE_OPTIONS=--openssl-legacy-provider; npm run docs:build
	- name: Test building examples (CJS)
	run: |
	cd examples/echo-bot-ts-cjs
	npm run build-sdk
	npm install
	npm run build

[eucyt]

I've confirmed npx zx ./line-openapi/tools/determine-change-type.mjs and npx zx ./line-openapi/tools/get-pr-info.mjs by Node.js 24

[eucyt]

Acutually, we can not test this CI but maybe OK.

[Yang-33]

you can test node ./scripts/update-version.mjs $VERSION

[eucyt]

I've confrimed 🙏

[Yang-33]

👍