ci: test to see if installing gcc-aarch64-linux-gnu works

Signed-off-by: Ivan Velickovic <[email protected]>

.github/workflows/ci.yaml

@@ -40,7 +40,7 @@ jobs:
         run: unzip microkit-sdk.zip && tar -xf microkit-sdk-1.2.6.tar.gz
       - name: Install dependencies (via apt)
         # 'expect' is only a dependency for CI testing
-        run: sudo apt update && sudo apt install -y make clang lld llvm qemu-system-arm device-tree-compiler expect
+        run: sudo apt update && sudo apt install -y make clang lld llvm qemu-system-arm device-tree-compiler expect gcc-aarch64-linux-gnu
       - name: Install Zig
         run: |
           wget https://ziglang.org/builds/zig-linux-x86_64-0.12.0-dev.3434+e90583f5d.tar.xz