fix: use global namespace for ValueError (#5)

Fixes exception:
```
Error: Class "vlw\ValueError" not found
```

Reviewed-on: https://codeberg.org/vlw/php-xenum/pulls/5

README.md

@@ -7,7 +7,7 @@ This library adds a few useful traits to your PHP Enums that compliment existing
 For example,
 
 ```php
-use \victorwesterlund\xEnum;
+use vlw\xEnum;
 
 enum HelloWorld: string {
     use xEnum;
@@ -28,12 +28,12 @@ Requires PHP 8.0 or newer
 
 1. **Install from composer**
     ```
-    composer require victorwesterlund/xenum
+    composer require vlw/xenum
     ```
 
 2. **`use` in your project**
     ```php
-    use \victorwesterlund\xEnum;
+    use vlw\xEnum;
     ```
 
 3. **`use` with your Enums**
@@ -76,7 +76,7 @@ enum HelloWorld: string {
     case BAZ = "QUX";
 }
 
-HelloWorld::fromName("BAR"); // HelloWorld::FOO
+HelloWorld::fromName("FOO"); // HelloWorld::FOO
 HelloWorld::fromName("MOM") // ValueError: 'MOM' is not a valid case for HelloWorld
 ```
 
@@ -100,7 +100,7 @@ enum HelloWorld: string {
     case BAZ = "QUX";
 }
 
-HelloWorld::tryFromName("BAR"); // HelloWorld::FOO
+HelloWorld::tryFromName("FOO"); // HelloWorld::FOO
 HelloWorld::tryFromName("MOM") // null
 ```
 

composer.json

@@ -1,18 +1,18 @@
 {
-    "name": "victorwesterlund/xenum",
+    "name": "vlw/xenum",
     "description": "PHP eXtended Enums. The missing quality-of-life features from PHP 8+ Enums",
     "type": "library",
     "license": "GPL-3.0-only",
     "authors": [
         {
             "name": "Victor Westerlund",
-            "email": "victor.vesterlund@gmail.com"
+            "email": "victor@vlw.se"
         }
     ],
     "minimum-stability": "dev",
     "autoload": {
         "psr-4": {
-            "victorwesterlund\\": "src/"
+            "vlw\\": "src/"
         }
     },
     "require": {}

src/xEnum.php

@@ -1,11 +1,11 @@
 <?php
 
-    namespace victorwesterlund;
+    namespace vlw;
 
     /*
         PHP eXtended Enums.
         The missing quality-of-life features from PHP 8+ Enums.
-        https://github.com/victorwesterlund/php-xenum
+        https://codeberg.org/vlw/php-xenum
     */
     trait xEnum {
         // Resolve enum case from enum name or return null
@@ -23,7 +23,7 @@
         // Throw a ValueError if Enum name is not found
         public static function fromName(?string $name): static {
             $case = self::tryFromName($name);
-            return $case ? $case : throw new ValueError("'{$name}' is not a valid case for enum " . self::class);
+            return $case ? $case : throw new \ValueError("'{$name}' is not a valid case for enum " . self::class);
         }
 
         // Return array of enum names