Sharding get started: update vshard version

Author: andreyaksenov

doc/code_snippets/snippets/sharding/instances.enabled/sharded_cluster/sharded_cluster-scm-1.rockspec

@@ -5,7 +5,7 @@ source  = {
 }
 
 dependencies = {
-    'vshard == 0.1.25'
+    'vshard == 0.1.26'
 }
 build = {
     type = 'none';