message: install python 3 in dockerfile for controller
diff: FROM debian:buster
  -RUN apt-get update && apt-get install build-essential python-pip lcov git curl libtinfo5 -y \
  - && pip install -U pip \
  - && pip install platformio codecov \
  - && platformio update
  +RUN apt-get update && \
  + apt-get install build-essential python3-pip lcov git curl libtinfo5 -y && \
  + pip3 install -U pip && \
  + pip3 install platformio codecov && \
  + platformio update
  WORKDIR /root/Ventilator
  COPY . ./
  