Fixed nonce to be base64

Change-Id: I17e9e617c4cbd7b56ff242153d6de1f8979f430a
diff --git a/lib/Kalamar/Plugin/CSP.pm b/lib/Kalamar/Plugin/CSP.pm
index 066df33..c9768aa 100644
--- a/lib/Kalamar/Plugin/CSP.pm
+++ b/lib/Kalamar/Plugin/CSP.pm
@@ -20,7 +20,7 @@
   $app->plugin('Util::RandomString' => {
     nonce => {
       alphabet => '1234567890abcdefghijklmnopqrstuvwxyz' .
-        'ABCDEFGHIJKLMNOPQRSTUVWXYZ!@#?(){}<>+-*',
+        'ABCDEFGHIJKLMNOPQRSTUVWXYZ+/',
       length   => 20
     }
   });