ci: Build the ubuntu-aarch64 binary with new ARM runners

The new GitHub arm runners are available, so we can use them to build
the ubuntu aarch64 binary instead of our custom machine.

Dockerfile

@@ -0,0 +1,20 @@
+# PostgREST Docker Hub image for aarch64.
+# The x86-64 is a single-static-binary image built via Nix, see:
+# nix/tools/docker/README.md
+
+FROM ubuntu:noble@sha256:80dd3c3b9c6cecb9f1667e9290b3bc61b78c2678c02cbdae5f0fea92cc6734ab AS postgrest
+
+RUN apt-get update -y \
+    && apt install -y --no-install-recommends libpq-dev zlib1g-dev jq gcc libnuma-dev \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY postgrest /usr/bin/postgrest
+
+EXPOSE 3000
+
+USER 1000
+
+# Use the array form to avoid running the command using bash, which does not handle `SIGTERM` properly. 
+# See https://docs.docker.com/compose/faq/#why-do-my-services-take-10-seconds-to-recreate-or-stop 
+CMD ["postgrest"]