chore(Docker): simplify timezone setup and use environment variable for timezone

Dockerfile

@@ -7,9 +7,7 @@ COPY proxy-go.${TARGETARCH} /app/proxy-go
 
 RUN mkdir -p /app/data && \
     chmod +x /app/proxy-go && \
-    apk add --no-cache ca-certificates tzdata && \
-    cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime && \
-    echo "Asia/Shanghai" > /etc/timezone
+    apk add --no-cache ca-certificates tzdata
 
 EXPOSE 80
 VOLUME ["/app/data"]

docker-compose.yml

@@ -6,4 +6,6 @@ services:
       - "3334:80"
     volumes:
       - ./data:/app/data
+    environment:
+      - TZ=Asia/Shanghai
     restart: always