Support for Solr 9?

[cornzz]

Hi there,
are you planning on supporting Solr version 9?

[kibertoad]

prs are welcome :)

[MarcusSorealheis]

I can do that. I need to use this library or one similar to rebuild the Solr Admi UI, so that's why it's potentially needed.

[kibertoad]

@MarcusSorealheis PR would be very much appreciated!