udpate danielstjules/stringy to use fork

Author: samsonasik

composer.json

@@ -13,7 +13,7 @@
         "clue/ndjson-react": "^1.2",
         "composer/semver": "^3.2",
         "composer/xdebug-handler": "^2.0",
-        "danielstjules/stringy": "^3.1",
+        "danielstjules/stringy": "dev-php81-return-type-willchange as 3.1.0",
         "doctrine/inflector": "^2.0",
         "ergebnis/json-printer": "^3.1",
         "idiosyncratic/editorconfig": "^0.1.3",
@@ -167,6 +167,12 @@
         "sort-packages": true,
         "platform-check": false
     },
+    "repositories" : [
+        {
+            "type" : "vcs",
+            "url" : "https://github.com/samsonasik/Stringy"
+        }
+    ],
     "minimum-stability": "dev",
     "prefer-stable": true
 }