fix docker file

dockerfile/caddy/Dockerfile

@@ -1,7 +1,7 @@
 FROM caddy:2.1.1-builder AS builder
 ENV GOPROXY https://goproxy.cn
 RUN caddy-builder \
-    github.com/lscgzwd/caddy-dnspod
+    github.com/caddy-dns/dnspod
 
 FROM caddy:2.1.1