L2SS-383: Don't buffer output of our tango-prometheus bridge to see the latest logs immediately

docker-compose/tango-prometheus-exporter/Dockerfile

@@ -12,4 +12,4 @@ RUN pip install -r /code/pip-requirements.txt
 WORKDIR /code
 ENV PYTHONPATH '/code/'
 
-CMD ["python" , "/code/collector.py"]
+CMD ["python", "-u", "/code/collector.py"]