add armv7 build

.github/workflows/armv7.yaml

@@ -0,0 +1,28 @@
+name: Docker AMD64
+
+on:
+  push:
+    branches: [ main ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Login to DockerHub
+      uses: docker/login-action@v2
+      with:
+        username: ${{ secrets.DOCKERHUB_USERNAME }}
+        password: ${{ secrets.DOCKERHUB_TOKEN }}
+    - name: Set up Docker Buildx
+      id: buildx
+      uses: crazy-max/ghaction-docker-buildx@v3
+      with:
+        buildx-version: latest
+        qemu-version: latest
+    - name: Available platforms
+      run: echo ${{ steps.buildx.outputs.platforms }}
+    - name: Run Buildx
+      run: |
+        docker buildx build \
+          --platform linux/arm/v7 \
+          --output "type=image,push=false" kerberos/base:beta