Remove prerelease tag from docs

docs/antora.yml

@@ -1,8 +1,6 @@
 name: contracts
 title: Contracts
-version: 3.x-rc
-prerelease: true
-display_version: 3.x-rc
+version: 3.x
 nav:
   - modules/ROOT/nav.adoc
   - modules/api/nav.adoc