ENH: added tox

.docker/Dockerfile

@@ -31,6 +31,9 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
   openjdk-14-jre-headless \
   openssl
 
+# for this pipeline
+RUN apt-get update && apt-get install -y \
+  tox
 RUN pip3 install docker-compose==1.25 pytest-shell
 
 RUN mkdir -p /opt/caosdb/build_docker/