Fix targetplatform for python

Author: waterfoul

Dockerfile

@@ -265,6 +265,7 @@ RUN apk add --update --no-cache gcc musl-dev libffi-dev rust cargo cmake make g+
 
 RUN mkdir /venvs
 
+ARG TARGETPLATFORM
 COPY --link --from=target-python /usr/local/bin/python3 /usr/local/bin/target-python3
 
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