Metadata manifest attribute not supported

The cloud foundry app manifest supports a metadata attribute for setting labels and annotations: https://docs.cloudfoundry.org/devguide/deploy-apps/manifest-attributes.html#metadata

However, this attribute seems to be ignored by the cf-java-client.

How to reproduce

Here is a minimal example that reproduces the issue:

ManifestV3 manifest = ApplicationManifestUtilsV3.read(Path.of("test-manifest-with-labels.yaml"));
ApplicationManifestUtilsV3.write(Path.of("test-manifest-result.yaml"), manifest);

Content of test-manifest-with-labels.yaml:

---
applications:
- name: test-app
  memory: 1G
  instances: 1
  metadata:
    labels:
      test-label: "test-value"

Content of test-manifest-result.yaml after the snippet above has run:

---
applications:
- name: test-app
  memory: 1G
  instances: 1

As you can see, the metadata information has been removed. When using the cf-java-client to deploy such a manifest, the metadata labels and annotations are therefore discarded. I would expect the attributes mentioned in the cloud foundry documentation to be supported by this client library, including the metadata attribute.

Begin at ApplicationManifestUtilsV3.read and write, using the provided manifest and output as the reproduction. Trace how metadata is represented during that round trip, preserve the labels and annotations described in the issue, and verify that the resulting manifest retains them.