Update Rust installation process in Dockerfile to use USTC mirrors

rocky9/Dockerfile

@@ -29,17 +29,17 @@ RUN dnf install --assumeyes --enablerepo=crb \
 
 RUN git config --global url."https://wangguofang.net/github.com/".insteadOf "https://github.com/"
 
-RUN RUSTUP_VERSION=1.28.2 \
-    && RUST_VERSION=1.98.0 \
+RUN export RUSTUP_DIST_SERVER="https://mirrors.ustc.edu.cn/rust-static" \
+    && export RUSTUP_UPDATE_ROOT="https://mirrors.ustc.edu.cn/rust-static/rustup" \
     && RUST_ARCH="$(uname -m)" \
     && curl --fail --location --output rustup-init \
-        "https://static.rust-lang.org/rustup/archive/${RUSTUP_VERSION}/${RUST_ARCH}-unknown-linux-gnu/rustup-init" \
+        "https://mirrors.ustc.edu.cn/rust-static/rustup/archive/1.28.2/${RUST_ARCH}-unknown-linux-gnu/rustup-init" \
     && chmod +x rustup-init \
     && ./rustup-init -y --default-toolchain none \
+    && rm rustup-init \
     && "$HOME/.cargo/bin/rustup" --version \
-    && "$HOME/.cargo/bin/rustup" toolchain install "$RUST_VERSION" --profile minimal \
-    && ln --symbolic "$HOME"/.cargo/bin/* /usr/local/bin/ \
-    && rm rustup-init
+    && "$HOME/.cargo/bin/rustup" toolchain install 1.98.0 --profile minimal \
+    && ln --symbolic "$HOME"/.cargo/bin/* /usr/local/bin/
 
 RUN curl --fail --location --output boost.tar.bz2 \
         https://mirrors.aliyun.com/blfs/conglomeration/boost/boost_1_83_0.tar.bz2 \