Adapt Python bindings to renamed communicator

Communicator was renamed to MpiCommunicator in https://git.rz.tu-bs.de/irmb/VirtualFluids_dev/-/merge_requests/233

pythonbindings/pyfluids-stubs/bindings/gpu/__init__.pyi

@@ -132,10 +132,10 @@ class BoundaryConditionFactory:
     def set_stress_boundary_condition(self, boundary_condition_type) -> None: ...
     def set_velocity_boundary_condition(self, boundary_condition_type) -> None: ...
 
-class Communicator:
+class MpiCommunicator:
     def __init__(self, *args, **kwargs) -> None: ...
     @staticmethod
-    def get_instance() -> Communicator: ...
+    def get_instance() -> MpiCommunicator: ...
     def get_number_of_process(self) -> int: ...
     def get_pid(self) -> int: ...