chore(ci): add aarch64 linux runner

Linux arm64 hosted runners is in public preview.
Enable and see if is is something we can have now.

https://github.blog/changelog/2025-01-16-linux-arm64-hosted-runners-now-available-for-free-in-public-repositories-public-preview/

.github/workflows/main.yml

@@ -122,6 +122,10 @@ jobs:
           os: ubuntu-latest
           rust: stable
           other: i686-unknown-linux-gnu
+        - name: Linux aarch64 stable
+          os: ubuntu-24.04-arm
+          rust: stable
+          other: i686-unknown-linux-gnu
         - name: Linux x86_64 beta
           os: ubuntu-latest
           rust: beta
@@ -130,6 +134,10 @@ jobs:
           os: ubuntu-latest
           rust: nightly
           other: i686-unknown-linux-gnu
+        - name: Linux aarch64 nightly
+          os: ubuntu-24.04-arm
+          rust: nightly
+          other: i686-unknown-linux-gnu
         - name: macOS aarch64 stable
           os: macos-14
           rust: stable
@@ -155,6 +163,9 @@ jobs:
     - uses: actions/checkout@v4
     - name: Dump Environment
       run: ci/dump-environment.sh
+    # workaround for https://github.com/actions/partner-runner-images/issues/26
+    - run: which rustup || sudo DEBIAN_FRONTEND=noninteractive apt-get -y install rustup
+      if: matrix.os == 'ubuntu-24.04-arm'
     # Some tests require stable. Make sure it is set to the most recent stable
     # so that we can predictably handle updates if necessary (and not randomly
     # when GitHub updates its image).