Improved string length calculation

Author: sorinsarca

README.md

@@ -42,7 +42,7 @@ the library's own API.
 
 ## Installation
 
-**Opis JSON Schema** is available on [Packagist] and it can be installed from a 
+**Opis JSON Schema** is available on [Packagist], and it can be installed from a 
 command line interface by using [Composer]. 
 
 ```bash
@@ -54,7 +54,7 @@ Or you could directly reference it into your `composer.json` file as a dependenc
 ```json
 {
     "require": {
-        "opis/json-schema": "^2.4"
+        "opis/json-schema": "^2.6"
     }
 }
 ```

composer.json

@@ -23,7 +23,7 @@
     "require": {
         "php": "^7.4 || ^8.0",
         "ext-json": "*",
-        "opis/string": "^2.0",
+        "opis/string": "^2.1",
         "opis/uri": "^1.0"
     },
     "require-dev": {

src/ValidationContext.php

@@ -481,7 +481,7 @@ public function getStringLength(): ?int
         $shared = $this->sharedObject();
 
         if (!isset($shared->stringLength)) {
-            $shared->stringLength = UnicodeString::from($this->currentData())->length();
+            $shared->stringLength = UnicodeString::getStringLength($this->currentData());
         }
 
         return $shared->stringLength;