Added support for PHP-8

Author: marc-mabe

.github/workflows/test.yml

@@ -23,6 +23,8 @@ jobs:
             CODE_COVERAGE: true
           - PHP_VERSION: 7.4
             CODE_COVERAGE: true
+          - PHP_VERSION: 8.0-rc
+            CODE_COVERAGE: true
 
     steps:
       - uses: actions/checkout@v2

composer.json

@@ -5,7 +5,7 @@
     "keywords": ["enum", "phpstan"],
     "license": "BSD-3-Clause",
     "require": {
-        "php": "^7.1",
+        "php": "^7.1 | ^8.0",
         "marc-mabe/php-enum": "^1.1 || ^2.0 || ^3.0 || ^4.0",
         "phpstan/phpstan": "^0.12"
     },