Add Root namespace for Cassandra class

cassandra/cassandra.php

@@ -26,15 +26,17 @@
  * limitations under the License.
  */
 
-/**
+namespace {
+
+    /**
      * The main entry point to the PHP Driver for Apache Cassandra.
      *
      * Use Cassandra::cluster() to build a cluster instance.
      * Use Cassandra::ssl() to build SSL options instance.
      * @link https://docs.datastax.com/en/developer/php-driver/latest/api/class.Cassandra/
      */
-final class Cassandra
-{
+    final class Cassandra
+    {
 
         /**
          * Consistency level ANY means the request is fulfilled as soon as the data
@@ -462,6 +464,8 @@ final class Cassandra
         {
         }
 
+    }
+
 }