Fix docker build

Dockerfile

@@ -1,9 +1,10 @@
 ARG ALPINE_VERSION=latest
 FROM alpine:$ALPINE_VERSION AS builder
 
+ARG RUST_VERSION=stable
+
 COPY Cargo.lock /usr/src/
 COPY Cargo.toml /usr/src/
-COPY src/ /usr/src/src/
 
 WORKDIR /usr/src