Update hashbrown requirement from 0.9 to 0.11

Updates the requirements on [hashbrown](https://github.com/rust-lang/hashbrown) to permit the latest version.
- [Release notes](https://github.com/rust-lang/hashbrown/releases)
- [Changelog](https://github.com/rust-lang/hashbrown/blob/master/CHANGELOG.md)
- [Commits](rust-lang/hashbrown@v0.9.0...v0.11.0)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

merkle/Cargo.toml

@@ -23,7 +23,7 @@ light-bitcoin-primitives = { path = "../primitives", default-features = false }
 light-bitcoin-serialization = { path = "../serialization", default-features = false, features = ["derive"] }
 
 [dev-dependencies]
-hashbrown = "0.9"
+hashbrown = "0.11"
 hex = "0.4"
 rand = "0.8"
 light-bitcoin-crypto = { path = "../crypto" }