Install requirements, remove rust and dev packages that are no longer needed, hopefully for a smaller docker layer size

Dockerfile

@@ -5,7 +5,9 @@ ARG CRYPTOGRAPHY_DONT_BUILD_RUST=1
 
 COPY requirements.txt /tmp/requirements.txt
 RUN apt-get update && apt-get install -y libssl-dev libffi-dev gcc libc-dev libxslt-dev zlib1g-dev rustc g++ --no-install-recommends && rm -rf /var/lib/apt/lists/* /var/cache/apt/*
-RUN pip3 install --upgrade pip && pip3 install --no-cache-dir -r /tmp/requirements.txt 
+
+# Update pip, install requirements, remove rust and dev packages that are no longer needed.
+RUN pip3 install --upgrade pip && pip3 install --no-cache-dir -r /tmp/requirements.txt && apt-get remove rustc *-dev --purge -y
 
  
 RUN [ ! -d "/app" ] && mkdir /app
@@ -25,7 +27,6 @@ ENV PYTHONUNBUFFERED=1
 # Attempt to store the triggered commit
 ARG SOURCE_COMMIT
 ARG SOURCE_BRANCH
-RUN apt-get remove rustc *-dev --purge -y
 RUN echo "commit: $SOURCE_COMMIT branch: $SOURCE_BRANCH" >/source.txt
 
 CMD [ "python", "./changedetection.py" , "-d", "/datastore"]