(maint) Bump version to 7.9.0-SNAPSHOT
(maint) Bump version to 7.9.0-SNAPSHOT

The next puppetserver release will include a major version bump of clj-parent,
which includes TLS 1.3 support, JRuby 9.3, and Clojure 1.11, among other things.
These changes are major enough to warrant a Y release of puppetserver.

puppetlabs/puppetserver,puppetlabs/puppetserver,puppetlabs/puppet-server,puppetlabs/puppet-server,puppetlabs/puppet-server,puppetlabs/puppetserver,puppetlabs/puppetserver