Update caddy Dockerfile (#1788)

* Change base image

caddy/Dockerfile

@@ -1,7 +1,15 @@
-FROM zuohuadong/caddy:alpine
+FROM golang:alpine
 
 LABEL maintainer="Huadong Zuo <admin@zuohuadong.cn>"
 
+RUN apk add --no-cache \
+    openssh \
+    git \
+    build-base && \
+    go get github.com/abiosoft/caddyplug/caddyplug \
+    && caddyplug install-caddy \
+    apk del build-base
+
 ARG plugins="cors"
 
 ## ARG plugins="cors cgi cloudflare azure linode"
@@ -12,7 +20,7 @@ RUN apk add --no-cache inotify-tools \
     && echo -e "#!/bin/sh\nwhile inotifywait -e modify /etc/caddy; do\n\tpkill caddy\ndone " >> /start.sh \
     && chmod +x /start.sh
 
-EXPOSE 80 443 2015
+EXPOSE 80 443
 
 WORKDIR /var/www/public