Use rust official image

Dockerfile

-FROM buildpack-deps:stretch
+FROM rust:latest
 MAINTAINER elois <c@elo.tf>
-LABEL version="1.41.0"
+LABEL version="1.47.0"
 LABEL description="CI for Rust projects"
 
-RUN apt-get update && \
-   apt-get install -y build-essential curl python-pip pkg-config libssl-dev sudo tar zip && \
-   apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
-   
-# install rustup
-RUN curl https://sh.rustup.rs -sSf | sh -s -- -y
-
-# rustup directory
-ENV PATH /root/.cargo/bin:$PATH
-
 # Install fmt and clippy
-RUN rustup component add rustfmt-preview && rustup component add clippy
+RUN rustup component add rustfmt && rustup component add clippy
 
 # install cargo deb and cargo deny and cargo tarpaulin
 RUN cargo install cargo-deb && cargo install cargo-deny && cargo install cargo-tarpaulin