Bump to 0.9.3 in README

Author: dwijnand

README.md

@@ -13,7 +13,7 @@ Latest:
 
 Add the following to your `project/plugins.sbt` or `~/.sbt/0.13/plugins/plugins.sbt` file:
 
-    addSbtPlugin("com.typesafe.sbt" % "sbt-git" % "0.9.2")
+    addSbtPlugin("com.typesafe.sbt" % "sbt-git" % "0.9.3")
 
 Prior to sbt 0.13.5: