Preserve semicolons in digest auth URI

[monsonego]

Summary

Preserve semicolon-delimited path parameters when Requests builds the digest-auth uri field.

Closes #6990.

Problem

HTTPDigestAuth.build_digest_header() currently rebuilds the request URI from the parsed path and query string only.

For URLs whose path includes semicolon-delimited parameters, that drops part of the original request target before Requests hashes it into the Authorization header.

Changes

• append urlparse(url).params back onto the digest-auth path before adding the query string
• add a regression test that covers a digest-auth URL whose path contains semicolon parameters

Testing

• PYTHONPATH=src python -m pytest tests/test_requests.py -k digestauth -q