Make it build with rustc 1.66.1, which is what's in Ubuntu 20.04

Docker/Dockerfile

@@ -5,4 +5,5 @@ RUN apt update && apt install -y wget git build-essential net-tools iproute2 ipe
 WORKDIR /root
 COPY . ramen
 WORKDIR /root/ramen
+RUN cargo update -p clap@4.4.7 --precise 4.1.4
 RUN cargo build --release --example=bench_doram