Set right pymongodata var for mongoDB 4.2

Author: fr4nc1sc0-r4m0n

tests/docker-compose.yml

@@ -205,7 +205,7 @@ volumes:
     driver: local
   pymongodata36:
     driver: local
-  pymongodata40:
+  pymongodata42:
     driver: local
   pyesdata7:
     driver: local