Remove the old schema directory, as it was moved to /config.

schema/fieldblock.schema.yml

-# Schema for the configuration files of the Field as Block module.
-
-block.settings.fieldblock:*:
-  type: block_settings
-  label: 'Field as Block'
-  mapping:
-    label_from_field:
-      type: boolean
-      lable: 'Use field label as block title'
-    field_name:
-      type: string
-      label: 'Field name'
-    formatter_id:
-      type: string
-      label: 'Format type machine name'
-    formatter_settings:
-      type: field.formatter.settings.[%parent.formatter_id]
-      label: 'Settings'
-fieldblock.settings:
-  type: config_object
-  label: 'Field Block settings'
-  mapping:
-    enabled_entity_types:
-      type: sequence
-      label: 'Entity types to create for which to create Field Blocks.'
-      sequence:
-        type: string
-        label: 'Entity type'