[pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Author: pre-commit-ci[bot]

src/cachier/exporters/prometheus.py

@@ -75,7 +75,6 @@ def __init__(
         self._server: Optional[Any] = None
         self._server_thread: Optional[threading.Thread] = None
 
-
         # Try to import prometheus_client if requested
         self._prom_client = None
         if use_prometheus_client and PROMETHEUS_CLIENT_AVAILABLE: