Bump bip39 to v2.0

We previously bumped the `bip39` version to 2.0 in the 0.2X release
branch. Back then, bumping it in `master` was erroneously considered unnecessary.

Here, we therefore bump the crate version in `master` after all.

crates/bdk/Cargo.toml

@@ -22,7 +22,7 @@ bdk_chain = { path = "../chain", version = "0.6.0", features = ["miniscript", "s
 
 # Optional dependencies
 hwi = { version = "0.7.0", optional = true, features = [ "miniscript"] }
-bip39 = { version = "1.0.1", optional = true }
+bip39 = { version = "2.0", optional = true }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 getrandom = "0.2"