+ fix exprOp test

Author: Vincent Le Henaff

tests/Doctrine/ODM/MongoDB/Tests/Aggregation/AggregationOperatorsProviderTrait.php

@@ -194,7 +194,7 @@ public static function provideExpressionOperators(): array
             ],
             'exprOp' => [
                 'expected' => ['$expr' => ['$eq' => ['$field', '$otherField']]],
-                'operator' => 'expr',
+                'operator' => 'exprOp',
                 'args' => [['$eq' => ['$field', '$otherField']]],
             ],
             'filter' => [