fix typo

Author: shootingfly

README.md

@@ -84,7 +84,7 @@ Then you can see,
 https://github.com/shootingfly/kemal-jbuilder-example
 
 ## Changelog
-+ **1.0.0**
++ **v1.0.0**
   + Support Crystal 1.0.0
 + **v0.3.0**
   + Support Tuple and Named Tuple