Install timezone database in Dockerfile

Added installation of timezone database to Dockerfile.

Author: kanao7

Dockerfile

@@ -1,12 +1,15 @@
 # 使用官方最新 builder 镜像
 FROM caddy:builder AS builder
 
-# 编译只包含 Cloudflare DNS 插件的 Caddy
+# 编译包含 Cloudflare DNS 插件的 Caddy
 RUN xcaddy build \
     --with github.com/caddy-dns/cloudflare
 
 # 使用官方最新运行镜像
 FROM caddy:latest
 
+# --- 新增部分：安装时区数据库 ---
+RUN apk add --no-cache tzdata
+
 # 替换默认的 caddy 二进制文件
 COPY --from=builder /usr/bin/caddy /usr/bin/caddy