Upgrade kn func in the Serverless Loan Broker example

See context: https://github.com/kiegroup/kogito-examples/pull/1444#discussion_r1000965590

In this JIRA, we should upgrade the kn function framework version of the example. As Lance explained in the comment, the kn func cli should be able to do it.
Besides that, we should run the tests and deploy the example in a knative environment to check if the nodejs functions are still valid.

See documentation: https://github.com/knative/func/blob/main/docs/function-templates/nodejs.md