chore(deps): update dependency lxml to v6

Author: renovate[bot]

requirements.txt

@@ -167,7 +167,7 @@ kiwisolver==1.4.8
     # via matplotlib
 lazy-object-proxy==1.10.0
     # via openapi-spec-validator
-lxml==5.3.2
+lxml==6.0.0
     # via pygef
 markupsafe==3.0.2
     # via