Enable Docker build caching

Dockerfile

@@ -1,16 +1,16 @@
-FROM docker.io/library/rust:1.81-bookworm as builder
+FROM docker.io/library/rust:1.81-bookworm AS builder
 
 ARG TARGET="x86_64-unknown-linux-gnu"
 ARG TARGET_CPU="native"
 
-RUN apt-get update -y && apt-get install -y linux-headers-generic git libc6-dev
-RUN rustup install stable
-
 WORKDIR /build
 COPY . /build
 
-RUN RUSTFLAGS="-C target-feature=+crt-static -C target-cpu=${TARGET_CPU}" cargo build --target ${TARGET} --bin laya-server --release
-RUN ls /build/target/release
+RUN --mount-type=cache,target=/var/cache/apt \
+    apt-get update -y && apt-get install -y linux-headers-generic git libc6-dev
+RUN --mount-type=cache,target=/usr/local/cargo/registry \
+    --mount-type=cache,target=/work/target \
+    rustup install stable && RUSTFLAGS="-C target-feature=+crt-static -C target-cpu=${TARGET_CPU}" cargo build --target ${TARGET} --bin laya-server --release
 
 FROM scratch
 ARG TARGET