Duplicate key "field.widget.settings.linkit" detected

My apologizes. Looks like it my own local issue.

@ruslan-piskarov what was your local issue? I've run into the same error

@matthew.h, I forgot to remove a path from https://www.drupal.org/project/linkit/issues/2712951 ✨ Linkit for Link field Fixed and it applied twice.

I am trying to upgrade linkit module from 6.0.0-beta4 to 6.0.0 and I have this error when running drush updb. I was using a patch from the same issue https://www.drupal.org/project/linkit/issues/2712951 ✨ Linkit for Link field Fixed but it was no longer applied in the version 6.0.0 so I removed it.
Apparently, the problem seems to happen when running database updates for the block_class module, more specifically in the hook block_class_update_20001() where I get the following error:
[notice] Update started: block_class_update_20001
[error] Invalid data type in config linkit.schema, found in file modules/contrib/linkit/config/schema/linkit.schema.yml: Duplicate key "field.widget.settings.linkit" detected at line 138 (near "# Schema for the Linkit formatter.").
[error] Update failed: block_class_update_20001
[error] Update aborted by: block_class_update_20001.

I believe this issue still needs to be looked at. The issue seems to be triggered by the block_class, however this needs to be fixed in the linkit module.

I had to remove the modules contrib folder and run composer install again. After that everything seems to be working fine.
I will close the issue again.