Pass NEO4J_USERNAME to tox target

naming as from downloaded auradb credentials

Author: FlorentinD

tox.ini

@@ -84,7 +84,7 @@ passenv =
 	PROJECT_ID
 
 	NEO4J_URI
-	NEO4J_USER
+	NEO4J_USERNAME
 	NEO4J_PASSWORD
 deps =
 	-r {toxinidir}/requirements/dev/notebook-aura-ci.txt
@@ -101,7 +101,7 @@ passenv =
 	PROJECT_ID
 
 	NEO4J_URI
-	NEO4J_USER
+	NEO4J_USERNAME
 	NEO4J_PASSWORD
 deps =
 	-r {toxinidir}/requirements/dev/notebook-aura-ci.txt