API phpunit 9 support

composer.json

@@ -16,12 +16,13 @@
         }
     ],
     "require": {
+        "php": "^7.3 || ^8.0",
         "silverstripe/cms": "^4",
         "silverstripe/versioned": "^1",
         "silverstripe/siteconfig": "^4"
     },
     "require-dev": {
-        "sminnee/phpunit": "^5.7",
+        "phpunit/phpunit": "^9.5",
         "squizlabs/php_codesniffer": "^3.0"
     },
     "autoload": {
@@ -30,11 +31,6 @@
             "SilverStripe\\VersionFeed\\Tests\\": "tests/"
         }
     },
-    "extra": {
-        "branch-alias": {
-            "dev-master": "2.x-dev"
-        }
-    },
     "minimum-stability": "dev",
     "prefer-stable": true
 }

phpunit.xml.dist

@@ -1,7 +1,9 @@
 <phpunit bootstrap="vendor/silverstripe/cms/tests/bootstrap.php" colors="true">
-    <testsuite name="Default">
-        <directory>tests/</directory>
-    </testsuite>
+    <testsuites>
+        <testsuite name="Default">
+            <directory>tests/</directory>
+        </testsuite>
+    </testsuites>
     <filter>
         <whitelist addUncoveredFilesFromWhitelist="true">
             <directory suffix=".php">src/</directory>

tests/VersionFeedFunctionalTest.php

@@ -36,7 +36,7 @@ class VersionFeedFunctionalTest extends FunctionalTest
      */
     protected $cache;
 
-    protected function setUp()
+    protected function setUp(): void
     {
         Director::config()->set('alternate_base_url', $this->baseURI);
 
@@ -64,7 +64,7 @@ class VersionFeedFunctionalTest extends FunctionalTest
         Versioned::set_reading_mode(Versioned::DEFAULT_MODE);
     }
 
-    protected function tearDown()
+    protected function tearDown(): void
     {
         Director::config()->set('alternate_base_url', null);