fix: add missing cd in Dockerfile

build/docker/twhelp/prod/Dockerfile

@@ -1,6 +1,6 @@
 FROM golang:1.19.1-alpine3.16 as builder
 
-WORKDIR /root
+WORKDIR /twhelp
 
 COPY go.mod go.sum ./
 RUN go mod download
@@ -9,14 +9,14 @@ RUN apk --no-cache add make
 
 COPY . .
 RUN make generate
-RUN CGO_ENABLED=0 go build -trimpath -o twhelp .
+RUN cd /twhelp && CGO_ENABLED=0 go build -trimpath -o twhelp .
 
 ######## Start a new stage from scratch #######
 FROM alpine:3.16
 
 RUN apk --no-cache add ca-certificates tzdata
 
-COPY --from=builder /root/twhelp /usr/bin/
+COPY --from=builder /twhelp/twhelp /usr/bin/
 
 EXPOSE 9234/tcp