drop support for PHP < 7.2, fix PHP 8.4 compatibility

.github/workflows/ci.yml

@@ -24,14 +24,14 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [ '5.5', '5.6', '7.0', '7.1', '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
+        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
         operating-system: [ ubuntu-latest ]
         composer_flags: [ '' ]
         include:
-          - php: '5.5'
+          - php: '7.2'
             composer_flags: '--prefer-lowest'
             operating-system: ubuntu-latest
-          - php: '7.0'
+          - php: '8.0'
             composer_flags: '--prefer-lowest'
             operating-system: ubuntu-latest
           - php: '8.1'

composer.json

@@ -12,13 +12,13 @@
     }
   ],
   "require": {
-    "php": "^5.5 || ^7.0 || ^8.0",
+    "php": "^7.2 || ^8.0",
     "ext-dom": "*",
     "ext-libxml": "*",
     "symfony/css-selector": "^2.7 || ^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^4.8.35 || ^5.7 || ^6.0 || ^7.5 || ^8.5.21 || ^9.5.10"
+    "phpunit/phpunit": "^8.5.21 || ^9.5.10"
   },
   "autoload": {
     "psr-4": {

src/Css/Property/Processor.php

@@ -66,7 +66,7 @@ private function cleanup($string)
      *
      * @return Property|null
      */
-    public function convertToObject($property, Specificity $specificity = null)
+    public function convertToObject($property, ?Specificity $specificity = null)
     {
         if (strpos($property, ':') === false) {
             return null;
@@ -91,7 +91,7 @@ public function convertToObject($property, Specificity $specificity = null)
      *
      * @return Property[]
      */
-    public function convertArrayToObjects(array $properties, Specificity $specificity = null)
+    public function convertArrayToObjects(array $properties, ?Specificity $specificity = null)
     {
         $objects = array();
 

src/Css/Property/Property.php

@@ -27,7 +27,7 @@ final class Property
      * @param string           $value
      * @param Specificity|null $specificity
      */
-    public function __construct($name, $value, Specificity $specificity = null)
+    public function __construct($name, $value, ?Specificity $specificity = null)
     {
         $this->name = $name;
         $this->value = $value;