Support for Laravel 8 and PHP 8.0 (#15)

* Upgrade dependencies.
* Upgrade phpunit schema.

composer.json

@@ -26,14 +26,14 @@
         }
     ],
     "require": {
-        "php": "^7.3",
+        "php": "^7.3|^8.0",
         "laravel/nova": "^3.0",
-        "illuminate/support": "^7.0",
-        "bensampo/laravel-enum": "^2.0"
+        "illuminate/support": "^7.0|^8.0",
+        "bensampo/laravel-enum": "^2.0|^3.0"
     },
     "require-dev": {
         "symfony/var-dumper": "^5.0",
-        "orchestra/testbench": "^5.0",
+        "orchestra/testbench": "^5.0|^6.0",
         "phpunit/phpunit": "^8.2|^9.0"
     },
     "autoload": {

phpunit.xml.dist

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<phpunit bootstrap="vendor/autoload.php"
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         bootstrap="vendor/autoload.php"
          backupGlobals="false"
          backupStaticAttributes="false"
          colors="true"
@@ -8,15 +9,16 @@
          convertNoticesToExceptions="true"
          convertWarningsToExceptions="true"
          processIsolation="false"
-         stopOnFailure="false">
+         stopOnFailure="false"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/9.3/phpunit.xsd">
+    <coverage>
+        <include>
+            <directory suffix=".php">src</directory>
+        </include>
+    </coverage>
     <testsuites>
         <testsuite name="Simple Squid Test Suite">
             <directory>tests</directory>
         </testsuite>
     </testsuites>
-    <filter>
-        <whitelist>
-            <directory suffix=".php">src</directory>
-        </whitelist>
-    </filter>
 </phpunit>