Plans for v8 (Node v20+, esm-only)

[Shinigami92]

While trying to support esm alongside cjs, more and more issues popping up 😢

I think the time has come to move forward and leave the cjs world behind. node-pg-migrate is also mostly anyways a CLI tool, and so hopefully it wont hurt the community that much.
However, as a first pre-step I setup a v7 branch, where in worst case we can e.g. backport features if possible.

Together with esm-only support, I will also remove support for Node v18, because import.meta.dirname is only a thing since Node v20.11.0.

Additionally TypeScript v4 support will be dropped.

Feel free to start some discussions below and provide feedback or help.