Release rune improvements

The release rune shouldn't publish more than 1 crate per minute(?) to prevent failures like:

Caused by:
  the remote server responded with an error (status 429 Too Many Requests): You have published too many updates to existing crates in a short period of time. Please try again after Mon, 04 Mar 2024 16:02:16 GMT or email help@crates.io to have your limit increased.