Automatically keep third-party modules up to date

[jvperrin]

It's easy for third-party modules to drift out of date and then need a large jump to get back to current when smaller incremental changes would be less painful. For instance, with #836 I've mainly left it around for the last 8 months hoping to get back to it to fix the few things that have broken by needing to upgrade a bunch of stuff all at once.

Some options (explored a bit by https://github.com/puppetlabs/r10k/blob/master/doc/updating-your-puppetfile.mkd):

• https://github.com/camptocamp/puppetfile-updater, seems like it's designed exactly for this task (updating Puppetfiles) and looks pretty minimal
• https://github.com/rnelson0/puppet-generate-puppetfile, looks pretty nice and can do some more advanced dependency resolution stuff that currently needs to be done manually, so that would be a benefit
• https://github.com/ocf/adelie (https://github.com/nikhiljha/adelie upstream), maintained more in-house so customizations would be easier to do, and this fits with the mission of automatically updating things. The main downside here is that it's not really designed for these kinds of updates (updating a large group of dependencies within the same repo) and would need like 30 config blocks to be made (no auto-discovery).
• Dependabot? (Puppet Dependency Support dependabot/dependabot-core#1281), seems like support for this will likely not be added due to understaffing and changing priorities