Update

Dockerfile

 MAINTAINER Drone CI/CD
 
 ARG HTTP_PROXY
-RUN echo $'\n\
-      Acquire::http  { Proxy "'${HTTP_PROXY}$'"; } \n\
+RUN echo '\
+      Acquire::http  { Proxy "'${HTTP_PROXY}'"; } \n\
       Acquire::https { Proxy "https://"; }; \n\
 '   >> /etc/apt/apt.conf.d/01-proxy