chore: add PHP 8.1 readonly properties (#4)

Reviewed-on: https://codeberg.org/vlw/php-globalsnapshot/pulls/4
Co-authored-by: vlw <victor@vlw.se>
Co-committed-by: vlw <victor@vlw.se>

README.md

@@ -1,6 +1,8 @@
 # php-globalsnapshot
 
-Capture the current state of all [PHP superglobal variables](https://www.php.net/manual/en/language.variables.superglobals.php); which can then be restored to that state at a later time.
+Capture the current state of all [PHP superglobal variables](https://www.php.net/manual/en/language.variables.superglobals.php) - which can then be restored to the state of capture at a later time.
+
+**Supports PHP 8.1+**
 
 Example use:
 ```php
@@ -24,12 +26,12 @@ echo $_ENV["hello"]; // echo: "world"
 
 1. Install with composer
 ```
-composer install victorwesterlund/globalsnapshot
+composer install vlw/globalsnapshot
 ```
 
 2. `use` in your project
 ```php
-use victorwesterlund\GlobalSnapshot;
+use vlw\GlobalSnapshot;
 ```
 
 3. Capture current superglobals with `capture()`

composer.json

@@ -1,18 +1,18 @@
 {
-    "name": "victorwesterlund/globalsnapshot",
+    "name": "vlw/globalsnapshot",
     "description": "Capture and restore the state of all PHP superglobals.",
     "type": "library",
     "license": "Unlicense",
     "authors": [
         {
             "name": "Victor Westerlund",
-            "email": "victor.vesterlund@gmail.com"
+            "email": "victor@vlw.se"
         }
     ],
     "minimum-stability": "dev",
     "autoload": {
         "psr-4": {
-            "victorwesterlund\\": "src/"
+            "vlw\\": "src/"
         }
     }
 }

src/GlobalSnapshot.php

@@ -1,20 +1,20 @@
 <?php
 
-    namespace victorwesterlund;
+    namespace vlw;
 
     // Capture the current state of all superglobals.
     // This will save a copy of all keys and values and any changes made to the superglobals 
     // can be restored to this point in time by calling $this->restore();
     class GlobalSnapshot {
         // Declare all PHP superglobals
-        private array $_ENV;
-        private array $_GET;
-        private array $_POST;
-        private array $_FILES;
-        private array $_SERVER;
-        private array $_COOKIE;
-        private array $_REQUEST;
-        private array $_SESSION;
+        private readonly array $_ENV;
+        private readonly array $_GET;
+        private readonly array $_POST;
+        private readonly array $_FILES;
+        private readonly array $_SERVER;
+        private readonly array $_COOKIE;
+        private readonly array $_REQUEST;
+        private readonly array $_SESSION;
 
 		// Declare additional PHP globals (for PHP 8.0+ compatability)
 		// These will not be captured, or altered by GlobalSnapshot