Update Dockerfile to using cache layer

Signed-off-by: jimmy <myemail@example.com>
Signed-off-by: piggy2303 <nguyentuananh23031997@gmail.com>

docker/Dockerfile

@@ -4,16 +4,19 @@ ARG NVIDIA_IMAGE=nvidia/cuda:12.2.0-devel-ubuntu20.04
 FROM $GOLANG_IMAGE AS build
 FROM $GOLANG_IMAGE AS gobuild
 ARG GOPROXY
+ADD go.mod /k8s-vgpu
+ADD go.sum /k8s-vgpu
+RUN go mod download
 ADD . /k8s-vgpu
 #RUN --mount=type=cache,target=/go/pkg/mod \
 #    cd /k8s-vgpu && make all
 RUN cd /k8s-vgpu && make all
 
 FROM $NVIDIA_IMAGE AS nvbuild
-COPY ./libvgpu /libvgpu
-WORKDIR /libvgpu
 ENV DEBIAN_FRONTEND=noninteractive
 RUN apt-get -y update; apt-get -y install cmake
+COPY ./libvgpu /libvgpu
+WORKDIR /libvgpu
 RUN bash ./build.sh
 
 FROM nvidia/cuda:12.4.1-base-ubuntu22.04