Add phpstan until level 7

tests/Spout/Writer/Common/Entity/SheetTest.php

@@ -25,7 +25,7 @@ class SheetTest extends TestCase
 
     /**
      * @param int $sheetIndex
-     * @param int $associatedWorkbookId
+     * @param string $associatedWorkbookId
      * @return Sheet
      */
     private function createSheet($sheetIndex, $associatedWorkbookId)
@@ -57,7 +57,7 @@ class SheetTest extends TestCase
     }
 
     /**
-     * @return array
+     * @return array<array>
      */
     public function dataProviderForInvalidSheetNames()
     {

tests/Spout/Writer/Common/Helper/CellHelperTest.php

@@ -10,7 +10,7 @@ use PHPUnit\Framework\TestCase;
 class CellHelperTest extends TestCase
 {
     /**
-     * @return array
+     * @return array<array>
      */
     public function dataProviderForTestGetColumnLettersFromColumnIndex()
     {

tests/Spout/Writer/Common/Manager/RowManagerTest.php

@@ -10,7 +10,7 @@ use PHPUnit\Framework\TestCase;
 class RowManagerTest extends TestCase
 {
     /**
-     * @return array
+     * @return array<mixed>
      */
     public function dataProviderForTestIsEmptyRow()
     {
@@ -26,7 +26,7 @@ class RowManagerTest extends TestCase
     /**
      * @dataProvider dataProviderForTestIsEmptyRow
      *
-     * @param array $cells
+     * @param array<Cell> $cells
      * @param bool $expectedIsEmpty
      * @return void
      */