Docs for next release

[manikmagar]

Once a new JBake version is released, create a copy of docs for next release version or something generic next-release-docs. It does need to reflect on jbake.org. This will help to update the documentation at the same time when features/bugfixes for next release are being merged into jbake/master. When the next JBake version is released, next-release-docs can be tagged as the latest docs.

[jonbullock]

Great idea 👍