chore(deps): update swoole/phpx dependency version

- Updated swoole/phpx from ~2.6.7 to ~2.6.8 in composer.json
- Bumped dependency version to latest stable release
- Maintained compatibility with existing codebase

composer.json

@@ -21,7 +21,7 @@
     "marcj/topsort": "^2.0",
     "symfony/var-dumper": "^8.0",
     "symfony/yaml": "^8.0",
-    "swoole/phpx": "~2.6.7",
+    "swoole/phpx": "~2.6.8",
     "ajaxray/ansikit": "^0.3",
     "ext-dom": "*"
   },