Remove smsapi/php-client 3.0 support (#27)

Author: psafarov

composer.json

@@ -15,7 +15,7 @@
         "php": ">=7.2",
         "illuminate/notifications": "~6.0 || ~7.0 || ~8.0 || ~9.0 || ~10.0 || ^11.0",
         "illuminate/support": "~6.0 || ~7.0 || ~8.0 || ~9.0 || ~10.0 || ^11.0",
-        "smsapi/php-client": "^1.8 || ^3.0"
+        "smsapi/php-client": "^1.8"
     },
     "require-dev": {
         "mockery/mockery": "^1.0",