Fix CLI's Docker file (#514)

Author: severb

docker-files/cli.Dockerfile

@@ -7,11 +7,10 @@ WORKDIR /tmp/pranadb
 
 # We want to populate the module cache based on the go.{mod,sum} files.
 COPY go.mod .
+COPY . .
 
 RUN go mod download
 
-COPY . .
-
 RUN go build -o ./out/prana ./cmd/prana
 
 # Start fresh from a smaller image