chore: refactor chr handling in SigningKey for the phpstan dependency (#88)

Co-authored-by: awu <andreas.wunderwald@westpress.de>

Author: wundii

composer.json

@@ -31,7 +31,7 @@
     "testcontainers/testcontainers": "1.0.4"
   },
   "require-dev": {
-    "phpstan/phpstan": "2.1.38",
+    "phpstan/phpstan": "2.1.39",
     "phpunit/phpunit": "11.5.50",
     "rector/rector": "2.3.6",
     "symplify/easy-coding-standard": "13.0.4"