update drone.yml and Dockerfile

Dockerfile

@@ -2,13 +2,15 @@ FROM debian:stable-slim
 MAINTAINER Drone CI/CD
 
 
-RUN cat >> /etc/apt/apt.conf.d/01-proxy <<-EOF \
-        Acquire::http  { Proxy "${HTTP_PROXY}"; } \
-        Acquire::https { Proxy "https://"; }; \
-      EOF
+RUN echo $'\n\
+      Acquire::http  { Proxy "'$HTTP_PROXY$'"; } \n\
+      Acquire::https { Proxy "https://"; }; \n\
+    >> /etc/apt/apt.conf.d/01-proxy
+
+
 
 RUN apt-get update && \
     apt-get --yes upgrade && \
-    apt-get --yes install ${BUILDDEPS}
+    apt-get --yes install $BUILDDEPS
 
 CMD [ "/bin/bash", "-c", "#(noop)" ]