feat(deps): support Symfony 8 (#68)

Add `| ^8` to symfony/process (require) and symfony/filesystem,
symfony/finder, symfony/http-client (require-dev).

Symfony 8.0 requires PHP 8.4+, so users on PHP 8.2/8.3 will continue
to resolve Symfony 7.x or 6.4 via Composer's platform check. The
library's lower bound stays at PHP 8.2.

Tested with PHP 8.5.6 + Symfony 8.0.x (prefer-stable) and PHP 8.2.31
with Symfony 6.4/5.x (prefer-lowest): 94/94 tests pass, zero PHPStan
errors, examples run cleanly.

Co-authored-by: Philippe S <philippe.segatori@wishgroupe.com>

Author: tigitz

composer.json

@@ -25,7 +25,7 @@
         "php": "^8.2",
         "nyholm/psr7": "^1.3",
         "psr/http-client": "^1.0",
-        "symfony/process": "^6.4 | ^7",
+        "symfony/process": "^6.4 | ^7 | ^8",
         "webmozart/assert": "^1.11"
     },
     "require-dev": {
@@ -39,9 +39,9 @@
         "phpstan/phpstan-phpunit": "^2",
         "phpunit/phpunit": "^11.0",
         "pixelrobin/php-feather": "^2",
-        "symfony/filesystem": "^5 |^6 | ^7",
-        "symfony/finder": "^5 |^6 | ^7",
-        "symfony/http-client": "^5 |^6 | ^7"
+        "symfony/filesystem": "^5 |^6 | ^7 | ^8",
+        "symfony/finder": "^5 |^6 | ^7 | ^8",
+        "symfony/http-client": "^5 |^6 | ^7 | ^8"
     },
     "suggest": {
         "symfony/http-client": "A PSR-18 Client implementation to use spellcheckers that relies on HTTP APIs"