Upgrade pyarrow 15 to 18 in tox

Author: brs96

tox.ini

@@ -22,7 +22,7 @@ envlist =
 
 	# Vary networkx versions only for relevant tests
 	py311-neo4j{4,5}-pandas1-pyarrow7-networkx{2,3}-main-nx
-	py311-neo4j{4,5}-pandas2-pyarrow15-networkx{2,3}-main-nx
+	py311-neo4j{4,5}-pandas2-pyarrow18-networkx{2,3}-main-nx
 	py311-networkx3-pullrequest-nx
 
 	# Notebooks