check for version bump in metadata.rb in CI jobs for commits on master
We often forget to bump version of cookbooks in metadata.rb
(we usually immediately follow that with a fixing commit). This results in multiple issues, for example, MRs being merged (to master branches of cookbook repos) that contain new Chef code, but are marked (tagged, versioned) with an old version. So as soon as the master branch is synced to the ops instance a cookbook is published that contains new, potentially breaking config that is published under the old version. This means that if a chef client tried to apply this config (that we expect to be version pinned) it would apply the new (potentially breaking) config. This probably hasn't bitten us badly yet for a number of reasons (caches on Chef server and on VMs, ops pipelines being cancelled if a new pipeline is created for the same branch), but it's a source of potential problems. Another issue is that this results in dirty git history. There's also the question of how quickly do we realize that we forgot to bump the version. We also rely on humans to "remember" to bump the version and I think that automatically checking this would make for a more reliable workflow.