Prepare for 2.12.4 release

Author: cowtowncoder

pom.xml

@@ -10,7 +10,7 @@
   <parent>
     <groupId>com.fasterxml.jackson</groupId>
     <artifactId>jackson-base</artifactId>
-    <version>2.12.4-SNAPSHOT</version>
+    <version>2.12.4</version>
   </parent>
 
   <groupId>com.fasterxml.jackson.core</groupId>

release-notes/VERSION-2.x

@@ -4,7 +4,7 @@ Project: jackson-databind
 === Releases === 
 ------------------------------------------------------------------------
 
-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)