Update services with new generator for RandomLib

Author: Robin Cawser

src/Vivait/StringGeneratorBundle/Resources/config/services.yml

@@ -17,4 +17,11 @@ services:
 
     vivait_generator.generator.secure_bytes:
         class: Vivait\StringGeneratorBundle\Generator\SecureBytesGenerator
-        arguments: [@security.secure_random]
+        arguments: [@security.secure_random]
+
+    vivait_generator.generator.secure_string:
+        class: Vivait\StringGeneratorBundle\Generator\SecureStringGenerator
+        arguments: [@vivait_generator.randomlib]
+
+    vivait_generator.randomlib:
+        class: RandomLib\Factory