Release 3.11.0.

* ConnectionBuilder::build shouldn't assume executor ticking. This fixes a deadlock when internal
  executor is disabled and interface is added to the builder.
* Don't panic in proxy builder. Return an error instead.
* Some optimizations in handshake code.
* Error out on invalid UTF-8 in the cookie auth data.
* Add `Error:MissingParameter` variant.
* Implement `Clone` for `InterfaceRef`.
* Add `SignalStream::name` getter.
* `SignalStream`'s inner lifetime need to be tied to that of proxy's inner lifetime, not the proxy
  itself. In case of macros, we can declare it as '`static'.
* Some fixes to docs.
* Dependency changes:
  * Enable 'io' feature of futures-util. if `async-io` is enabled.
  * Add optional dep on `async-fs`.
  * update nix to 0.26.