Upgrade Jackson dependency to version 2.21.4. (#426)

Author: blackwinter

build.gradle

@@ -36,7 +36,7 @@ subprojects {
       'equalsverifier':   '3.8.2',
       'everit':           '1.14.6',
       'guava':            '32.0.1-jre',
-      'jackson':          '2.21.1',
+      'jackson':          '2.21.4',
       'jdk':              '11',
       'jdom':             '2.0.6.1',
       'jena':             '4.10.0',