Update dependency lxml to v6 [SECURITY]

Author: renovate[bot]

pyproject.toml

@@ -23,7 +23,7 @@ isort = "^4.3.21"
 mypy = "^0.910"
 black = "^23.0.0"
 fastapi = "^0.89.0"
-lxml = "^4.9.1"
+lxml = "^6.0.0"
 starlette = "^0.22.0"
 mock = "^4.0.1"
 hiro = "^0.5.1"