v5.0.0-alpha.0

Hi folks! This major rewrite is finally looking the way I want. I still would like to add automated tests for compatibility with redis clusters, and more documentation would probably be helpful.

These changes essentially amount to a full rewrite, and include:

• rewritten in TypeScript
• dropped support for legacy APIs (callback, disposer)
• introduction of new, more modern APIs (fixes #73)
• removal of bluebird promises
• improved error handling (fixes #43)
• stats collection for better observability
• choice of ioredis as the only redis library for testing
• publication as an ES module
• use of GitHub actions for CI

I just published a pre-release on NPM as 5.0.0-alpha.0 and plan on merging this to main shortly, so that fixes or improvements can be more easily made against it, as it progresses towards a full release. Any patches to the current version will be made in the v4 branch once this is merged.

Any help testing this and vetting the changes would be appreciated!