Use gmp operator overload instead of gmp_pow for certain PHP versions (…

…#215)

Use gmp operator overload instead of gmp_pow for certain PHP versions

.github/workflows/ci.yml

@@ -14,6 +14,7 @@ jobs:
           - 8.0
           - 8.1
           - 8.2
+          - 8.3
     steps:
       - name: Checkout
         uses: actions/checkout@v4

src/SimpleJWT/Util/BigNum.php

@@ -217,6 +217,9 @@ protected function _div($a, $b) {
     function _pow($base, $exp) {
         if (is_object($exp) && ($exp instanceof \GMP))
             $exp = gmp_intval($exp);
+        /** @disregard P1006  */
+        if (version_compare(PHP_VERSION, '8.2.26', '==') || version_compare(PHP_VERSION, '8.3.14', '=='))
+            return ($base ** $exp);
         return gmp_pow($base, $exp);
     }