Allow lxml 6 (#3219)

* Allow lxml 6
rdflib builds with lxml 6.0.1 - the current latest release.

* chore: run poetry lock

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Co-authored-by: Edmond Chuc <[email protected]>

Author: jhgit

poetry.lock

@@ -76,8 +76,8 @@ networkx = ["networkx >=2,<4"]
 html = ["html5rdf >=1.2.1,<2"]
 # lxml support is optional, it is used only for parsing XML-formatted SPARQL results
 lxml = [
-    'lxml >=4.8.0,<6.0; python_version <"3.11"',
-    'lxml >=4.9.3,<6.0; python_version >="3.11"',
+    'lxml >=4.8.0,<7.0; python_version <"3.11"',
+    'lxml >=4.9.3,<7.0; python_version >="3.11"',
 ]
 orjson = ["orjson >=3.9.14,<4"]