Use deployctl so import maps work

[zabihexes]

To support import maps deployctl needs to be used.

https://deno.com/deploy/docs/runtime-api#web-apis

https://github.com/denoland/deployctl/blob/main/action/README.md

[zabihexes]

I suppose just changing readme is enough.

[andythedishwasher]

I've tried that from a local clone of this repo with the deployctl CLI tool directly, but I'm getting a 'module not found' when I try to cache the Discordeno dependency. Also seems to be some issue with an underlying preact dependency for the sift import. Any clue what might be going on with that?