Fix protobuf dependency (#794)

* Explicitly install protobuf instead of relying on it coming externally

* change from dockerfile to requirements

Author: tgerdesnv

requirements.txt

@@ -21,6 +21,7 @@ matplotlib>=3.3.4
 numba>=0.51.2
 pdfkit>=0.6.1
 prometheus_client>=0.9.0
+protobuf
 psutil>=5.8.0
 pyyaml>=5.3.1
 requests>=2.24.0