Run tests on PHP 8.5 (#10)

* Run CI on PHP 8.5
* Use `ramsey/composer-install` to benefit from dependency caching
* Update export-ignore list

Co-authored-by: Theodore Brown <theodorejb@outlook.com>

Author: gsteel

.gitattributes

@@ -1,2 +1,7 @@
 tests/ export-ignore
 .github/ export-ignore
+.gitattributes export-ignore
+.gitignore export-ignore
+.php-cs-fixer.php export-ignore
+composer.lock export-ignore
+phpstan.neon export-ignore

.github/workflows/php.yml

@@ -7,11 +7,11 @@ jobs:
 
     strategy:
       matrix:
-        php: [ '8.2', '8.3', '8.4' ]
+        php: [ '8.2', '8.3', '8.4', '8.5' ]
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Docs: https://github.com/shivammathur/setup-php
       - name: Setup PHP
@@ -26,7 +26,7 @@ jobs:
         run: composer validate --strict
 
       - name: Install Composer dependencies
-        run: composer install --no-progress
+        uses: "ramsey/composer-install@v3"
 
       - name: Run PHPUnit
         run: composer test