docker: use itzaname docker proxy to avoid getting rate-limited

validation/Containerfile

@@ -1,6 +1,6 @@
 # Using the `rust-musl-builder` as base image, instead of
 # the official Rust toolchain
-FROM docker.io/clux/muslrust:stable AS chef
+FROM registry.itzana.me/docker-proxy/clux/muslrust:stable AS chef
 USER root
 RUN cargo install cargo-chef
 WORKDIR /app
@@ -17,7 +17,7 @@ RUN cargo chef cook --release --target x86_64-unknown-linux-musl --recipe-path r
 COPY . .
 RUN cargo build --release --target x86_64-unknown-linux-musl --bin maps-validation
 
-FROM docker.io/alpine:latest AS runtime
+FROM registry.itzana.me/docker-proxy/alpine:3.21 AS runtime
 RUN addgroup -S myuser && adduser -S myuser -G myuser
 COPY --from=builder /app/target/x86_64-unknown-linux-musl/release/maps-validation /usr/local/bin/
 USER myuser