Fix#13342 adapt docker provider build for containerd storage

plugins/providers/docker/driver.rb

@@ -31,6 +31,10 @@ def build(dir, **opts, &block)
         # In this case, docker buildkit is enabled. Its format is different
         # from standard docker
         matches = result.scan(/writing image .+:([^\s]+)/i).last
+        if !matches
+          # Check for outout of docker using containerd backend store
+          matches = result.scan(/exporting manifest list .+:([^\s]+)/i).last
+        end
         if !matches
           if podman?
             # Check for podman format when it is emulating docker CLI.

test/unit/plugins/providers/docker/driver_test.rb

@@ -207,6 +207,16 @@
       end
     end
 
+    context "using buildkit with containerd backend output" do
+      let(:stdout) { "exporting manifest list sha256:1a2b3c4d done" }
+
+      it "builds a container with buildkit docker (containerd)" do
+        container_id = subject.build("/tmp/fakedir")
+
+        expect(container_id).to eq(cid)
+      end
+    end
+
     context "using podman emulating docker CLI" do
       let(:stdout) { "1a2b3c4d5e6f7g8h9i10j11k12l13m14n16o17p18q19r20s21t22u23v24w25x2" }