refactor: Remove GMP dependency and switch to BC math for arithmetic operations.

Author: gustavofreze

.github/workflows/ci.yml

@@ -38,7 +38,7 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
-      - name: Use PHP 8.2
+      - name: Use PHP ${{ env.PHP_VERSION }}
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ env.PHP_VERSION }}