[Netfilter] Keep musl-dev, update pip

data/Dockerfiles/netfilter/Dockerfile

@@ -5,9 +5,9 @@ ENV XTABLES_LIBDIR /usr/lib/xtables
 ENV PYTHON_IPTABLES_XTABLES_VERSION 12
 ENV IPTABLES_LIBDIR /usr/lib
 
-RUN apk add --virtual .build-deps gcc python3-dev musl-dev libffi-dev openssl-dev \
-  && apk add -U python3 iptables ip6tables tzdata \
-  && pip3 install --upgrade python-iptables==0.13.0 redis ipaddress dnspython \
+RUN apk add --virtual .build-deps gcc python3-dev libffi-dev openssl-dev \
+  && apk add -U python3 iptables ip6tables tzdata musl-dev \
+  && pip3 install --upgrade pip python-iptables==0.13.0 redis ipaddress dnspython \
   && apk del .build-deps
 
 COPY server.py /