Update Dockerfile

Dockerfile

@@ -4,7 +4,7 @@ WORKDIR /app
 COPY . .
 ENV CGO_ENABLED=0
 RUN apk --update --no-cache add git
-RUN git submodule update --init --recursive
+RUN git clone https://github.com/wyx2685/sing-box_mod.git
 RUN go mod download
 RUN go build -v -o V2bX -tags "sing xray hysteria2 with_reality_server with_quic with_grpc with_utls with_wireguard with_acme with_gvisor"