replace data class with class to fix issue #21

[kazemcodes]

after applying code to my own project everything works fine, and there was no issue, and everything should work like before without any migrations.
if possible please release a new update for lyricist, as I want to migrate my project to lyricist.
@DevSrSouza @adrielcafe

[kazemcodes]

when will this be reviewed?
@DevSrSouza @adrielcafe

[DevNatan]

Thx for your contribution @kazemcodes!!

Maybe non-immutable class and fields can lead into something but we will see it later.

Apparently this modification is intended for a small number of Lyricist users, very specific, so can you

• Place it under a flag like lyricist.useRegularClassToPreventOverflow (as clear as possible) so that it can be defined by user choice. See LyricistConfig as reference
• Revert SDK version changes as it is not in the scope of this PR

[adrielcafe]

Since this change only affects the xml processor (which should be triggered only once for migration purposes) I've done a similar implementation but using interface instead.

Thanks for your bug report!