Notice regarding XML and YAML package bundles

[marticliment]

Important: As of UniGetUI 3.2.1-beta5, it will be not possible to create XML and YAML bundles anymore.

• Existing XML and YAML bundles can be imported, via internal YAML/XML-to-JSON conversion before deserialization.
• XML and YAML import will be removed in the future.
• XML and YAML bundles can be also converted to JSON bundles using an older UniGetUI version. Then, the JSON bundle will be importable to newer UniGetUI versions.

Note: XML and YAML bundles are almost never used (XML+YAML account for 0.7~1.3% of all the bundles), and it is difficult to maintain the three different methods, especially with the recently introduced changes.
Note: UBUNDLE bundles are internally formatted as JSON, so they won't be affected by this change.