Add support for YouTube field type

The change looks reasonable, although it'd be great if there would be a test and require-dev (as mentioned) before the merge.
Also, the patch should be changed to MR to allow tests run.

in version single_content_sync 1.4.7 → the GenericField plugin was added in the ✨ Create default plugin for content entities Needs review , which provides support for all types of entities and fields

Thanks for checking the issue!