Make tests compatible with PHPUnit 8

Author: cweiske

composer.json

@@ -27,6 +27,6 @@
         "ext-mbstring": "May require the mbstring PHP extension"
     },
     "require-dev": {
-        "phpunit/phpunit": "7.*|8.*|9.*"
+        "phpunit/phpunit": "8.*"
     }
 }

tests/Text_LanguageDetectTest.php

@@ -14,13 +14,13 @@
 
 class Text_LanguageDetectTest extends \PHPUnit\Framework\TestCase {
 
-    function setUp()
+    function setUp(): void
     {
         $this->x = new Text_LanguageDetect();
         $this->xproxy = new PrivProxy($this->x);
     }
 
-    function tearDown ()
+    function tearDown(): void
     {
         unset($this->x);
     }