Fix phpunit.xml and psalm.xml

Author: PhrozenByte

phpunit.xml

@@ -15,7 +15,11 @@
   ~ License-Filename: LICENSE
   -->
 
-<phpunit bootstrap="vendor/autoload.php">
+<phpunit
+    bootstrap="./vendor/autoload.php"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/7.4/phpunit.xsd"
+>
     <testsuites>
         <testsuite name="phpunit-array-asserts">
             <directory>./tests/Unit</directory>

psalm.xml

@@ -1,4 +1,20 @@
-<?xml version="1.0"?>
+<?xml version="1.0" encoding="utf-8" ?>
+<!--
+  ~ PHPUnitArrayAssertions - Array-related PHPUnit assertions for API testing.
+  ~
+  ~ @copyright Copyright (c) 2021, Daniel Rudolf (<https://www.daniel-rudolf.de>)
+  ~
+  ~ This file is copyrighted by the contributors recorded in the version control
+  ~ history of the file, available from the following original location:
+  ~
+  ~ <https://github.com/PhrozenByte/phpunit-throwable-asserts/blob/master/psalm.xml>
+  ~
+  ~ @license http://opensource.org/licenses/MIT The MIT License
+  ~
+  ~ SPDX-License-Identifier: MIT
+  ~ License-Filename: LICENSE
+  -->
+
 <psalm
     errorLevel="4"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"