Lower minimum PHP to 8.1 and restore CI matrix

Hub and saas still run PHP 8.2, so this package must support it.
No 8.4-specific features are used in the source code.

Author: devlob

.github/workflows/tests.yml

@@ -9,15 +9,18 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
-    name: Tests
+    strategy:
+      matrix:
+        php: ['8.1', '8.2', '8.3']
+    name: PHP ${{ matrix.php }}
 
     steps:
       - uses: actions/checkout@v4
 
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '8.4'
+          php-version: ${{ matrix.php }}
           coverage: none
 
       - name: Cache Composer dependencies

composer.json

@@ -4,7 +4,7 @@
     "type": "library",
     "license": "MIT",
     "require": {
-        "php": "^8.4"
+        "php": "^8.1"
     },
     "require-dev": {
         "pestphp/pest": "^2.0|^3.0"