Fixed prometheus multiprocessing registry (#620)

Author: FadingFog

taskiq/middlewares/prometheus_middleware.py

@@ -84,17 +84,22 @@ def startup(self) -> None:
         This function starts prometheus server.
         It starts it only in case if it's a worker process.
         """
-        from prometheus_client import REGISTRY, start_http_server  # noqa: PLC0415
+        from prometheus_client import (  # noqa: PLC0415
+            CollectorRegistry,
+            start_http_server,
+        )
         from prometheus_client.multiprocess import (  # noqa: PLC0415
             MultiProcessCollector,
         )
 
         if self.broker.is_worker_process:
             try:
-                MultiProcessCollector(REGISTRY)
+                registry = CollectorRegistry()
+                MultiProcessCollector(registry)
                 start_http_server(
                     port=self.server_port,
                     addr=self.server_addr,
+                    registry=registry,
                 )
             except OSError as exc:
                 logger.debug("Cannot start prometheus server: %s", exc)