Update link to default release process definition

Author: xuwei-k

README.md

@@ -257,7 +257,7 @@ I highly recommend to make yourself familiar with the [State API](https://www.sc
 
 ### Can we finally customize that release process, please?
 
-Yes, and as a start, let's take a look at the [default definition](https://github.com/sbt/sbt-release/blob/v1.0.15/src/main/scala/ReleasePlugin.scala#L250) of `releaseProcess`:
+Yes, and as a start, let's take a look at the [default definition](https://github.com/sbt/sbt-release/blob/v1.4.0/src/main/scala/ReleasePlugin.scala#L262-L274) of `releaseProcess`:
 
 #### The default release process