Revert "chore(ci): Add a dependency updater action to run weekly"

[effigies]

Reverts #83

Looks like (hasundue/molt-action#33) molt is not going to bother adding lockfile 4 support, since Deno will be shipping deno update (denoland/deno#26219) in the nearish future.

Not sure what to expect in terms of an action for automation, but so be it.

In the meantime, you can do:

deno run -A jsr:@molt/cli --write
deno test -A src/ --parallel
git add deno.json deno.lock