Fix make_custom_pi_os to work in docker

Author: guysoft

src/Dockerfile

@@ -19,6 +19,7 @@ RUN set -x \
     && rm -rf /var/lib/apt/lists/*
 
 RUN ln -s /CustomPiOS/nightly_build_scripts/custompios_nightly_build /usr/bin/build
+RUN ln -s /usr/bin/python3 /usr/bin/python
 
 COPY . /CustomPiOS
 

src/Dockerfile.arm32v7

@@ -34,6 +34,7 @@ RUN set -x \
     && rm -rf /var/lib/apt/lists/*
 
 RUN ln -s /CustomPiOS/nightly_build_scripts/custompios_nightly_build /usr/bin/build
+RUN ln -s /usr/bin/python3 /usr/bin/python
 
 COPY . /CustomPiOS