Signxml

- Mark SHA1 as deprecated

- Aggregate verification settings in SignatureConfiguration dataclass

- Mark all dataclasses in API as frozen

- Add ability to assert expected signature location

- Add ability to assert expected signature algorithms

- Add ability to assert expected digest algorithms

- Add MGF1 ("RSASSA-PSS without parameters") algorithm identifiers

- Remove PSS ("RSASSA-PSS with parameters") and EdDSA algorithm
identifiers (given low usage and no interop examples, we will not be
implementing PSS parameters for now; EdDSA key info additionally has
no standardized way to serialize it)

- Add debug logging of canonicalization outputs

- Documentation and formatting improvements

- Add XAdES support

- Migrate all configuration inputs to enums (string identifiers are still supported, but will be deprecated in a future version)

- Migrate structured data inputs to dataclasses

- Deprecate excise_empty_xmlns_declarations

- Documentation and test infrastructure improvements

- Clean up top level signxml and signxml.xades namespaces

- Stop using default_backend for cryptography, it is no longer required

- Drop Python 3.6 support (200)

- Do not excise any empty `xmlns=""` declarations by default. This behavior is now configurable as follows


signer = XMLSigner()
signer.excise_empty_xmlns_declarations = True
signer.sign(...)


verifier = XMLVerifier()
verifier.excise_empty_xmlns_declarations = True
verifier.verify(...)


- Documentation and autoformatting improvements

- Excise empty xmlns declarations only in signature, not in payload

- Add pyinstaller support to signxml (188)

- Documentation, test infrastructure, and code organization improvements

- Unlimit cryptography version constraint. Fixes 177

- Bump pyOpenSSL compat range; add dep version strategy note

- Allow the combination of X509Data and KeyValue when they represent the same public key (169)

- Use self.namespaces signature properties "Object" element (167)