chore(deps): update flume requirement from 0.11 to 0.12

Updates the requirements on [flume](https://github.com/zesterer/flume) to permit the latest version.
- [Changelog](https://github.com/zesterer/flume/blob/master/CHANGELOG.md)
- [Commits](https://github.com/zesterer/flume/commits/0.12)

---
updated-dependencies:
- dependency-name: flume
  dependency-version: 0.12.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

monoio/Cargo.toml

@@ -22,7 +22,7 @@ socket2 = { version = "0.5", features = ["all"] }
 memchr = "2.7"
 
 bytes = { version = "1", optional = true }
-flume = { version = "0.11", optional = true }
+flume = { version = "0.12", optional = true }
 mio = { version = "0.8", features = [
     "net",
     "os-poll",