(maint) Update version to 6.3.0-SNAPSHOT
(maint) Update version to 6.3.0-SNAPSHOT

Update in preparation for the 6.3.0 release.

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