Revert "Bump jackson.version from 2.9.9 to 2.10.0.pr1"

This reverts commit 7b3685b.

Author: beatngu13

pom.xml

@@ -53,7 +53,7 @@
 		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
 		<junit.jupiter.version>5.5.1</junit.jupiter.version>
 		<logback.version>1.2.3</logback.version>
-		<jackson.version>2.10.0.pr1</jackson.version>
+		<jackson.version>2.9.9</jackson.version>
 	</properties>
 
 	<scm>