fix jar version in README.md

Author: hayasshi

README.md

@@ -5,5 +5,5 @@ This is an example of GitBucket plug-in. This plug-in provides code snippet repo
 ## Instllation
 
 1. Hit `./sbt.sh package` in the root directory of this repository.
-2. Copy `target/scala-2.11/gitbucket-gist-plugin_2.11-1.1.jar` into `GITBUCKET_HOME/plugins`.
+2. Copy `target/scala-2.11/gitbucket-gist-plugin_2.11-1.2.jar` into `GITBUCKET_HOME/plugins`.
 3. Restart GitBucket.