Ractor V0.11.0 is released!

This is a major API break since we're deprecating actor monitors. Having not found a reasonable use-case for them, we've experienced that utilizing DashMap's for every actor is causing a large memory hit (~34kb/actor). In an effort to support higher-actor count services, this is a significant amount of memory utilization.

By removing the DashMap's and having just a single HashMap for the supervision tree, this can save us a significant amount of memory.

However removing monitors is an API break.

This also has a ~50-60% increase in actor spawning performance.

See #260 FMI