replace docker with podman

.github/actions/build_apko/action.yml

@@ -13,13 +13,19 @@ inputs:
     description: "GitHub authorization token"
     required: true
 
-# Linux runner only (Docker required)
+# Linux runner only (podman required)
 runs:
   using: "composite"
   steps:
+    - name: Install podman
+    shell: bash
+    run: |
+      sudo apt-get update
+      sudo apt-get install -y podman
+
     - name: Log in to the Container registry
-      id: docker-login
-      uses: docker/login-action@f4ef78c080cd8ba55a85445d5b36e214a81df20a # tag=v2.1.0
+      id: podman-login
+      uses: redhat-actions/podman-login@v1
       with:
         registry: ${{ inputs.registry }}
         username: ${{ github.actor }}
@@ -28,7 +34,6 @@ runs:
     - name: Build apko images
       shell: bash
       run: |
-        # TODO: replace with apko publish
         if [ -z "${{ inputs.apkoConfig }}" ]; then
           echo "Building all images in image"
           for imageConfig in image/apko/*.yaml; do
@@ -38,9 +43,9 @@ runs:
             registry=${{ inputs.registry }}/edgelesssys/apko-${imageName}
             outTar=$imageName.tar
 
-            docker run -v "$PWD":/work cgr.dev/chainguard/apko build $imageConfig $registry $outTar
-            docker load < $outTar
-            docker push $registry
+            podman run -v "$PWD":/work cgr.dev/chainguard/apko build $imageConfig $registry $outTar
+            podman load < $outTar
+            podman push $registry
 
           done
         else
@@ -50,7 +55,7 @@ runs:
           registry=${{ inputs.registry }}/edgelesssys/apko-${imageName}
           outTar=$imageName.tar
 
-          docker run -v "$PWD":/work cgr.dev/chainguard/apko build ${{ inputs.apkoConfig }} $registry $outTar
-          docker load < $outTar
-          docker push $registry
+          podman run -v "$PWD":/work cgr.dev/chainguard/apko build ${{ inputs.apkoConfig }} $registry $outTar
+          podman load < $outTar
+          podman push $registry
         fi