Attempt compatibility with PHP8

Author: paulbalandan

.github/workflows/build.yml

@@ -28,18 +28,18 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-versions: ['7.3', '7.4']
+        php-versions: ['7.3', '7.4', '8.0']
 
     steps:
       - name: Checkout
         uses: actions/checkout@v2
 
       - name: Setup PHP, with composer and extensions
-        uses: shivammathur/setup-php@master
+        uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php-versions }}
           tools: composer
-          extensions: curl, intl, mbstring, xdebug
+          extensions: intl, xdebug
           coverage: xdebug
 
       - name: Validate composer.json

composer.json

@@ -10,17 +10,22 @@
         }
     ],
     "require": {
-        "php": "^7.3",
+        "php": "^7.3 || ^8.0",
         "ext-tokenizer": "*",
-        "friendsofphp/php-cs-fixer": "^2.16"
+        "friendsofphp/php-cs-fixer": "^2.18"
+    },
+    "replace": {
+        "symfony/polyfill-php70": "*",
+        "symfony/polyfill-php72": "*",
+        "symfony/polyfill-php73": "*"
     },
     "conflict": {
         "liaison/cs-config": "*"
     },
     "require-dev": {
         "phpstan/phpstan": "^0.12",
         "phpstan/phpstan-strict-rules": "^0.12",
-        "phpunit/phpunit": "^9.4"
+        "phpunit/phpunit": "^9.5"
     },
     "config": {
         "optimize-autoloader": true,