Translation plugin

Hi @jules-colle and @stevish, thank you for the plugin!

I’d like to translate it into Russian, but it’s not properly prepared for localization, see the warning on the plugin page in GlotPress:
https://translate.ww.wp.xz.cn/projects/wp-plugins/cf7-conditional-fields

ERROR: Your plugin slug is cf7-conditional-fields, but there seems no Text Domain: defined in contact-form-7-conditional-fields.php! To correctly internationlize your plugin you will need it.

Could you please fix this to prepare the plugin for localization? Thanks!