Update block2 requirement from 0.5 to 0.6

---
updated-dependencies:
- dependency-name: block2
  dependency-version: 0.6.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -19,7 +19,7 @@ serde_repr = "0.1"
 
 [target.'cfg(target_os = "macos")'.dependencies]
 objc2 = "0.6"
-block2 = "0.5"
+block2 = "0.6"
 objc2-core-foundation = "0.3"
 objc2-foundation = { version = "0.3", features = ["NSString"] }
 objc2-app-kit = { version = "0.3", features = ["NSSharingService", "NSView", "NSResponder", "NSWindow"] }