Change data provider methods to public
 use PHPUnit\Framework\TestCase;
 final class SomeTest extends TestCase
 {
     /**
      * @dataProvider provideData()
      */
     public function test()
     {
     }
-    protected static function provideData()
+    public static function provideData()
     {
         yield [1];
     }
 }
                        Configure your rector.php:
<?php
use Rector\Config\RectorConfig;
use Rector\PHPUnit\PHPUnit100\Rector\Class_\PublicDataProviderClassMethodRector;
return RectorConfig::configure()
    ->withRules([
        PublicDataProviderClassMethodRector::class,
    ]);