v1.3.1

This is a maintenance release focused on aligment with latest CF Java Client version and build improvements.

• Bump to CF Java Client v5.6.0.RELEASE (#453)
• Remove Bintray from release pipelines (#440)
• Enabled nightly builds to drive out failures (#450)
• Bump to concourse-release-scripts-0.3.4-SNAPSHOT for 1.3.x (#460)
• Test against Java 11 in GH Actions (#438)
• Docs: Mention the use-spring-application-json property (#443, @pg200)

Thanks to all contributors