docs: remove WIP from upgrade recipe

Author: triceo

docs/src/modules/ROOT/pages/upgrade-and-migration/upgrade-to-latest-version.adoc

@@ -57,7 +57,7 @@ Every upgrade note indicates how likely your code will be affected by that chang
 The upgrade recipe often lists the changes as they apply to Java code.
 We kindly ask Kotlin and Python users to translate the changes accordingly.
 
-=== Upgrade from 1.12.0 to 1.13.0 (Work in progress)
+=== Upgrade from 1.12.0 to 1.13.0
 
 icon:exclamation-triangle[role=red] `@ConstraintConfiguration` deprecated
 [%collapsible%open]