fix(ValidVariableName): Allow underscore variable names for plugin annotation...

            if ($extendsName !== false && strpos($extendsName, 'ConfigEntity') !== false) {

                return;

            }

            // Plugin annotations may have underscores in class properties.

            // For example, see \Drupal\Core\Field\Annotation\FieldFormatter.

            // The only class named "Plugin" in Drupal core is

            // \Drupal\Component\Annotation\Plugin while many Views plugins

            // extend \Drupal\views\Annotation\ViewsPluginAnnotationBase.

            if ($extendsName !== false && in_array(

                $extendsName,

                [

                 'Plugin',

                 'ViewsPluginAnnotationBase',

                ]

            ) !== false

            ) {

                return;

            }

            $implementsNames = $phpcsFile->findImplementedInterfaceNames($classPtr);

            if ($implementsNames !== false && in_array('AnnotationInterface', $implementsNames) !== false) {

                return;

            }

        }//end if

        $error = 'Class property %s should use lowerCamel naming without underscores';

        $data  = array($tokens[$stackPtr]['content']);

$UppperCamelName = 0;

$lowerCamelName = 1;

class TestAnnotationProperties extends Plugin {

  /**

   * The entity_type.

   *

   * @var string

   */

  public $entity_type;

}

class TestAnnotationProperties2 extends ViewsPluginAnnotationBase {

  /**

   * The entity_type.

   *

   * @var string

   */

  public $entity_type;

}

class TestAnnotationProperties3 implements AnnotationInterface {

  /**

   * The entity_type.

   *

   * @var string

   */

  public $entity_type;

}