Use ARM runners for arm64 builds

Author: garyttierney

.github/workflows/push.yml

@@ -15,17 +15,19 @@ permissions:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.platform.runner }}
     strategy:
       fail-fast: false
       matrix:
         platform:
-          - linux/amd64
-          - linux/arm64
+          - docker: linux/amd64
+            runner: ubuntu-latest
+          - docker: linux/arm64
+            runner: ubuntu-latest-arm
     steps:
       - name: Prepare
         run: |
-          platform=${{ matrix.platform }}
+          platform=${{ matrix.platform.docker }}
           echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
 
       - name: Check out the repository
@@ -54,7 +56,7 @@ jobs:
         id: build
         uses: docker/build-push-action@v6
         with:
-          platforms: ${{ matrix.platform }}
+          platforms: ${{ matrix.platform.docker }}
           labels: ${{ steps.meta.outputs.labels }}
           tags: ${{ env.REGISTRY_IMAGE }}
           outputs: type=image,push-by-digest=true,name-canonical=true,push=true