add 5.1 to e2e tests

Author: OskarDamkjaer

.github/workflows/pr-e2e-tests.yml

@@ -17,6 +17,7 @@ jobs:
           - 3.5
           - 4.3
           - 4.4
+          - 5.1.0
         neo4j-edition:
           - community
           - enterprise