Getting Error : "You must declare "ids" as a unique array of fields in your source settings." while trying to migrate for paragraph in Drupal 8
As the error message suggests, ids needs to be an array, e.g.

source:
  plugin: csv
  path: '/var/www/html/drupal/author.csv'
  header_row_count: 1
  ids: 
    id:
      type: integer


Do note that you're in a YML file here; it looks like you might have tried to use PHP array syntax.