fix test

Author: melihovv

.gitignore

@@ -1,3 +1,4 @@
 /vendor
 /.idea
 /composer.lock
+/.phpunit.result.cache

tests/LaravelEnvValidatorTest.php

@@ -28,15 +28,15 @@ public function it_has_the_right_error_message()
             $envValidator = EnvValidatorFactory::buildFromLaravelConfig();
             $envValidator->validate();
         } catch (Exception $e) {
-            $this->assertContains(
+            $this->assertStringContainsString(
                 'VAR_1',
                 $e->getMessage()
             );
-            $this->assertContains(
+            $this->assertStringContainsString(
                 'VAR_2',
                 $e->getMessage()
             );
-            $this->assertContains(
+            $this->assertStringContainsString(
                 'required',
                 $e->getMessage()
             );