Remove existing python3

Author: pandaninjas

Dockerfile

@@ -16,4 +16,7 @@ RUN cd Python-${VERSION} && ./configure && make -j$(nproc) && make install
 RUN rm -rf Python-${VERSION} Python-${VERSION}.tgz /etc/apt/sources.list.d/debsrc.list
 
 RUN echo -e "[global]\nextra-index-url=https://www.piwheels.org/simple" > /etc/pip.conf 
-# replicate raspberry pi os pip.conf
+# replicate raspberry pi os pip.conf
+
+# remove existing python3
+RUN apt remove python3