Add support for newer version of spring by upgrading Jackson

[jrgleason]

Currently this project is using Jackson 2, so it is causing me issues when I try to use it in a Jackson 3 project. I know there are workarounds for now but can we get a version that uses Jackson 3

GIVEN I am a developer
AND I am using Spring v4
WHEN I compile a project
AND I am using okya-jwt-verifier-java
AND I am trying to use Jackson 3
AND exclude Jackson 2
THEN I should be able to compile.