Merge pull request #16 from pestphp/fix-timeout-calculate-return-type…

…-error

Fix error with timeout calculation return type

src/MutationTest.php

@@ -107,7 +107,7 @@ private function calculateTimeout(): int
             ->getInitialTestSuiteDuration()
             ->seconds();
 
-        return $initialTestSuiteDuration + max(5, $initialTestSuiteDuration * 0.2);
+        return $initialTestSuiteDuration + max(5, (int) ($initialTestSuiteDuration * 0.2));
     }
 
     public function hasFinished(): bool