add readonly modifiers wherever possible

lib/Providers/Rng/HashRNGProvider.php

@@ -8,7 +8,7 @@ use function in_array;
 
 class HashRNGProvider implements IRNGProvider
 {
-    public function __construct(private string $algorithm = 'sha256')
+    public function __construct(private readonly string $algorithm = 'sha256')
     {
         $algos = array_values(hash_algos());
         if (!in_array($this->algorithm, $algos, true)) {

lib/Providers/Rng/OpenSSLRNGProvider.php

@@ -6,7 +6,7 @@ namespace RobThree\Auth\Providers\Rng;
 
 class OpenSSLRNGProvider implements IRNGProvider
 {
-    public function __construct(private bool $requirestrong = true)
+    public function __construct(private readonly bool $requirestrong = true)
     {
     }
 

lib/TwoFactorAuth.php

@@ -28,13 +28,13 @@ class TwoFactorAuth
     private static array $_base32lookup = array();
 
     public function __construct(
-        private ?string          $issuer = null,
-        private int              $digits = 6,
-        private int              $period = 30,
-        private Algorithm        $algorithm = Algorithm::Sha1,
-        private ?IQRCodeProvider $qrcodeprovider = null,
-        private ?IRNGProvider    $rngprovider = null,
-        private ?ITimeProvider   $timeprovider = null
+        private readonly ?string   $issuer = null,
+        private readonly int       $digits = 6,
+        private readonly int       $period = 30,
+        private readonly Algorithm $algorithm = Algorithm::Sha1,
+        private ?IQRCodeProvider   $qrcodeprovider = null,
+        private ?IRNGProvider      $rngprovider = null,
+        private ?ITimeProvider     $timeprovider = null
     ) {
         if ($this->digits <= 0) {
             throw new TwoFactorAuthException('Digits must be > 0');