Enhance Dockerfile with versioning support

Add build arguments and environment variables for versioning.

Author: stefanogermano

Dockerfile

@@ -2,10 +2,13 @@ FROM python:3
 
 COPY . .
 
+ARG APP_VERSION
+ENV VCS_VERSIONING_PRETEND_VERSION=${APP_VERSION}
+
 RUN apt-get update && \
     apt-get install -y bubblewrap && \
     rm -rf /var/lib/apt/lists/*
 
 RUN pip install .
 
-CMD ese-run
+CMD ["ese-run"]