Bump pyo3 to 0.22 (#822)

* Bump pyo3 from 0.21.2 to 0.22.0 in /src/_bcrypt

Bumps [pyo3](https://github.com/pyo3/pyo3) from 0.21.2 to 0.22.0.
- [Release notes](https://github.com/pyo3/pyo3/releases)
- [Changelog](https://github.com/PyO3/pyo3/blob/main/CHANGELOG.md)
- [Commits](PyO3/pyo3@v0.21.2...v0.22.0)

---
updated-dependencies:
- dependency-name: pyo3
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

* Fix build on pyo3 0.22

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: alex

src/_bcrypt/Cargo.lock

@@ -6,7 +6,7 @@ edition = "2018"
 publish = false
 
 [dependencies]
-pyo3 = { version = "0.21", features = ["abi3"] }
+pyo3 = { version = "0.22", features = ["abi3"] }
 bcrypt = "0.15"
 bcrypt-pbkdf = "0.10.0"
 base64 = "0.22.1"

src/_bcrypt/Cargo.toml

@@ -13,7 +13,7 @@
 #![deny(rust_2018_idioms)]
 
 use base64::Engine;
-use pyo3::prelude::PyBytesMethods;
+use pyo3::prelude::{PyBytesMethods, PyModuleMethods};
 use pyo3::PyTypeInfo;
 use std::convert::TryInto;
 use std::io::Write;
@@ -25,6 +25,7 @@ pub const BASE64_ENGINE: base64::engine::GeneralPurpose = base64::engine::Genera
 );
 
 #[pyo3::prelude::pyfunction]
+#[pyo3(signature = (rounds=None, prefix=None))]
 fn gensalt<'p>(
     py: pyo3::Python<'p>,
     rounds: Option<u16>,
@@ -128,16 +129,15 @@ fn checkpw(py: pyo3::Python<'_>, password: &[u8], hashed_password: &[u8]) -> pyo
 }
 
 #[pyo3::prelude::pyfunction]
+#[pyo3(signature = (password, salt, desired_key_bytes, rounds, ignore_few_rounds=false))]
 fn kdf<'p>(
     py: pyo3::Python<'p>,
     password: &[u8],
     salt: &[u8],
     desired_key_bytes: usize,
     rounds: u32,
-    ignore_few_rounds: Option<bool>,
+    ignore_few_rounds: bool,
 ) -> pyo3::PyResult<pyo3::Bound<'p, pyo3::types::PyBytes>> {
-    let ignore_few_rounds = ignore_few_rounds.unwrap_or(false);
-
     if password.is_empty() || salt.is_empty() {
         return Err(pyo3::exceptions::PyValueError::new_err(
             "password and salt must not be empty",