docs(changelog): 3.1.0.Final -> 3.1.0-SNAPSHOT for now
Will leave it as snapshot until released so that when it's pulled into Apiman website it does
not give misleading impression that the release has been done.
= Changelog
-All notable changes to Apiman will be documented here, as of Apiman 3.0.0.Final.
+All notable changes to Apiman will be documented here (as of Apiman 3).
// tag::3.1.0.Final[]
-== 3.1.0.Final
+== 3.1.0-SNAPSHOT
=== Added
