Update Node.js Version to 18 or Later used in Github actions

[quag-cactus]

We are currently using Node.js 16 for our flow of GitHub Actions.

However, it has been announced that support for Node.js 16 will end earlier than anticipated, on September 11, 2023 ( https://nodejs.org/en/blog/announcements/nodejs16-eol). So, It is necessary to upgrade the node.js version to 18 or later.

I have already conducted tests using node.js 18.16.1 in a forked repository. The results showed that only the following packages displayed warnings. I guess they don't affect the integraion test and actual functionality.

• [email protected]
• @es-joy/[email protected] (dependency of eslint-plugin-jsdoc)

Thus, my only task is to update the version of eslint-plugin-jsdoc to newer.