Fix arm64 cargo plugin installation [skip ci]

Author: Claudio Raimondi

Dockerfile

@@ -145,12 +145,13 @@ ARG COPTFLAGS="-O2 ${COPTFLAGS}"
 WORKDIR /opt
 
 RUN ./install-uv.sh -q
-RUN ./install-rust.sh -y -q --profile minimal --component rustfmt --target ${target_arch_rust} 
+RUN ./install-rust.sh -y -q --profile minimal --component rustfmt --target ${target_arch_rust} --default-host=${target_arch_rust}
 
 ENV PATH="/root/.cargo/bin:/root/.local/bin:${PATH}"
 
 WORKDIR /opt/lightningd
 
+#TODO: set these in env instead of file?
 RUN mkdir -p .cargo && tee .cargo/config.toml <<EOF
 [target.${target_arch_rust}]
 linker = "${target_arch}-gcc"