Start 2.20 branch; update 2.x to 2.21

Author: cowtowncoder

pom.xml

@@ -5,7 +5,7 @@
   <parent>
     <groupId>com.fasterxml.jackson</groupId>
     <artifactId>jackson-base</artifactId>
-    <version>2.20.0</version>
+    <version>2.21.0-SNAPSHOT</version>
   </parent>
   <groupId>com.fasterxml.jackson.integtest</groupId>
   <artifactId>jackson-integration-tests</artifactId>