Merge branch '2.12' into 2.13

Author: cowtowncoder

release-notes/VERSION-2.x

@@ -61,7 +61,7 @@ Project: jackson-databind
   via `AsNull`
 - Add `mvnw` wrapper
 
-2.12.4 (not yet released)
+2.12.4 (06-Jul-2021)
 
 #3139: Deserialization of "empty" subtype with DEDUCTION failed
  (reported by JoeWoo; fix provided by drekbour@github)