Release v0.5.0 (#60)

* Bump version

* Bump to v0.5.0

Author: paulhauner

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "milhouse"
-version = "0.4.0"
+version = "0.5.0"
 description = "Persistent binary merkle tree"
 edition = "2021"
 license = "Apache-2.0"