Support PHP8 (#16)

Author: janlam7

.github/workflows/main.yaml

@@ -12,7 +12,7 @@ jobs:
 
     strategy:
       matrix:
-        php-versions: ['7.3', '7.4']
+        php-versions: ['7.3', '7.4', '8.0']
     name: PHP ${{ matrix.php-versions }}
     steps:
       -   uses: actions/checkout@v2

composer.json

@@ -4,7 +4,7 @@
     "description": "Provide a real database, safe for testing purposes",
     "license":     "MIT",
     "require": {
-        "php":          "^7.3",
+        "php":          "^7.3|^8.0",
         "doctrine/orm": "^2.5.4"
     },
     "require-dev": {