fix: use nightly img

Dockerfile

@@ -5,7 +5,7 @@
 #COPY . .
 #RUN npm run sass
 #
-FROM rust:slim as rust
+FROM rustlang/rust:nightly-slim as rust
 WORKDIR /src
 RUN apt-get update && apt-get install -y git pkg-config libssl-dev make
 RUN mkdir src && echo "fn main() {}" > src/main.rs