update docker build

docker/Dockerfile

@@ -20,8 +20,7 @@ COPY /pkg ./pkg
 RUN go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.26
 RUN go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.1
 
-RUN --mount=type=cache,target=$GOPATH/pkg/mod \
-    go mod download
+RUN go mod download
 
 # Go build environment
 # --------------------
@@ -33,9 +32,7 @@ ARG CGO_ENABLED=0
 # build proto files
 RUN sh ./scripts/build/proto.sh
 
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    --mount=type=cache,target=$GOPATH/pkg/mod \
-    go build -ldflags="-w -s -X 'main.Version=${version}'" -a -o ./bin/app ./cmd/app && \
+RUN go build -ldflags="-w -s -X 'main.Version=${version}'" -a -o ./bin/app ./cmd/app && \
     go build -ldflags '-w -s' -a -o ./bin/migrate ./cmd/migrate && \
     go build -ldflags '-w -s' -a -o ./bin/ready ./cmd/ready
 
@@ -43,9 +40,7 @@ RUN --mount=type=cache,target=/root/.cache/go-build \
 # -------------------
 FROM base AS porter-test
 
-RUN --mount=type=cache,target=/root/.cache/go-build \
-    --mount=type=cache,target=$GOPATH/pkg/mod \
-    go test ./...
+RUN go test ./...
 
 # Webpack build environment
 # -------------------------