Update Dockerfile

Dockerfile

 
 ARG HTTP_PROXY
 RUN echo $'\n\
-      Acquire::http  { Proxy "'$HTTP_PROXY$'"; } \n\
+      Acquire::http  { Proxy "'${HTTP_PROXY}$'"; } \n\
       Acquire::https { Proxy "https://"; }; \n\
 '   >> /etc/apt/apt.conf.d/01-proxy
 
 ARG BUILDDEPS
 RUN apt-get update && \
     apt-get --yes upgrade && \
-    apt-get --yes install $BUILDDEPS
+    apt-get --yes install ${BUILDDEPS}
 
 CMD [ "/bin/bash", "-c", "#(noop)" ]