- Align behaviour of expect_references with docs (#279).

  Passing `expect_references=True` to `verify(...)` now results in a list
  of `verify_results`, irrespective of the number of references in the
  signature.

- Accept lxml 6.x

- Add options to exclude the C14N Transform element in signatures (#274)

- Use Python 3.9 compatible typing expression

This release contains security fixes for two security advisories:

- Signature verification with HMAC is vulnerable to an algorithm confusion attack
  (GHSA-6vx8-pcwv-xhf4)

- Signature verification with HMAC is vulnerable to a timing attack
  (GHSA-gmhf-gg8w-jw42)

- Fix issue with support for deprecated PyOpenSSL certificates

- Fully remove the ca_path parameter; add docs for signature location pinning

- XAdES signing: remove duplicate timezone information from `SigningT…

…ime` (#266)

- Verifier: Accept PyOpenSSL cert input, add deprecation warning

- Replace PyOpenSSL with Cryptography (#260)

  - This is a major infrastructure change that replaces core
    certificate parsing, key processing, signature validation, and
    certificate chain validation functions previously provided by
    PyOpenSSL with those provided by Cryptography. Care was taken to
    preserve the exisitng API, including exception types, but many
    error messages raised in various error conditions have changed. If
    you see unexpected behavior and you have reason to believe it is
    incorrect, please file an issue.

  - Breaking change: the ca_path parameter, previously used to specify
    CA certificate stores, is no longer supported. Use the ca_pem_file
    parameter instead.

- Raise error when invalid certificate string is passed as input to signer

- Fix public key matching for ECDSA (#245)

- Update upper bound on lxml dependency to allow lxml 5

- Bump minimum dependency versions to align with Ubuntu 20.04

- Test and release infrastructure improvements

- Use dataclass.replace in SignatureReference construction. Fixes #231