Allow default header comment accept multi copyrights

Author: natanfelles

src/Config.php

@@ -319,11 +319,15 @@ public function setHeaderComment(string $header) : static
 
     public function setDefaultHeaderComment(
         string $packageName,
-        string $copyright = ''
+        array | string $copyright = []
     ) : static {
+        $copyright = (array) $copyright;
         $copyrightLines = "\n";
         if ($copyright) {
-            $copyrightLines .= "\n" . '(c) ' . $copyright . "\n";
+            $copyrightLines .= "\n";
+            foreach ($copyright as $cr) {
+                $copyrightLines .= '(c) ' . $cr . "\n";
+            }
         }
         $header = <<<EOF
             This file is part of {$packageName}.{$copyrightLines}

tests/ConfigTest.php

@@ -54,5 +54,11 @@ public function testDefaultHeaderComment() : void
         $header = $this->config->getRules()['header_comment']['header'];
         self::assertStringContainsString('Bazz', $header);
         self::assertStringContainsString('(c) Acme', $header);
+        $this->config->setDefaultHeaderComment('Bazz', ['Acme', 'OK']);
+        // @phpstan-ignore-next-line
+        $header = $this->config->getRules()['header_comment']['header'];
+        self::assertStringContainsString('Bazz', $header);
+        self::assertStringContainsString('(c) Acme', $header);
+        self::assertStringContainsString('(c) OK', $header);
     }
 }