backlog for express-session@2.x

I’m opening this issue to discuss a potential version 2 of express-session. Here are some things that could be included in this version 2:

- Drop support for Node.js <18.
- Code modernization (Migrate to new ES syntax)
- Add type definition files (.d.ts).
- Use cookie v1, which introduces breaking changes.
- Add support for HTTP/2 (there’s a PR that partially addresses this https://github.com/expressjs/session/pull/908).
- Fix the res.end error: https://github.com/expressjs/session/pull/751.
- Do not remove the legacy session: https://github.com/expressjs/session/pull/419
- https://github.com/expressjs/session/pull/977.
- Provide an asynchronous API: https://github.com/expressjs/session/issues/952 https://github.com/fastify/session/pull/78.
- Improve debug mode: https://github.com/expressjs/session/pull/708 https://github.com/expressjs/session/pull/986.

These are the issues and PRs I’ve identified as relevant for a version 2. I’d appreciate any feedback to move forward with modernizing this package.

cc: @expressjs/session-collaborators @UlisesGascon @expressjs/express-tc