fix: dockerfile

Dockerfile

@@ -3,7 +3,7 @@ FROM rust
 WORKDIR /usr/src/app
 
 # first cargo files to cache dependencies
-COPY Cargo.toml Cargo.lock ./
+COPY Cargo.toml ./
 RUN mkdir src && \
     echo "fn main() {println!(\"if you see this, the build broke\")}" > src/main.rs && \
     cargo build --release