use blacksmith arm machine for arm builds

Author: brendan-kellam

.github/workflows/ghcr-publish.yml

@@ -29,7 +29,7 @@ jobs:
           - platform: linux/amd64
             runs-on: blacksmith-4vcpu-ubuntu-2404
           - platform: linux/arm64
-            runs-on: ubuntu-24.04-arm
+            runs-on: blacksmith-8vcpu-ubuntu-2204-arm
 
     steps:
       - name: Prepare