Make sure to build linux/arm64 for default branch

.github/workflows/main.yml

@@ -95,6 +95,9 @@ jobs:
     permissions:
       packages: write
       contents: write
+    env:
+      PLATFORMS: ${{ github.ref == format('refs/heads/{0}', github.event.repository.default_branch) && 'linux/amd64,linux/arm64' || 'linux/amd64' }}
+
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -131,15 +134,6 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 
-      - name: Set Platforms Based on Branch
-        id: set_platforms
-        run: |
-          if [ "${GITHUB_REF}" == "refs/heads/${{ github.repository.default_branch }}" ]; then
-            echo "PLATFORMS=linux/amd64,linux/arm64" >> $GITHUB_ENV
-          else
-            echo "PLATFORMS=linux/amd64" >> $GITHUB_ENV
-          fi
-
       - name: Docker meta
         id: meta
         uses: docker/metadata-action@v5