Changehange node.js version in readme.md from 12.x to 18.x

Checklist

[x] I have ensured my pull request is not behind the main or master branch of the original repository.
[x] I have rebased all commits where necessary so that reviewing this pull request can be done without having to merge it first.
[x] I have written a commit message that passes commitlint linting.
[x] I have ensured that my code changes pass linting tests.
[x] I have ensured that my code changes pass unit tests.
[x] I have described my pull request and the reasons for code changes along with context if necessary.