Add VERSIONS-SKIP to handle projects stuck on bad latest versions

[Nuru]

what

• Add a new optional file to each package directory: VERSIONS-SKIP
• Do not auto-update a package to a version listed in VERSIONS-SKIP

why

Some projects' latest versions are defective in some way. Usually, those projects release a later version that fixes the issue, and we can proceed normally, but occasionally the projects languish in this broken state. In that case, we try and fail to auto-update the project twice a day, leaving broken PRs open indefinitely.

With this new feature, we can mark those versions as bad and prevent auto-update from re-opening PRs for them.

references

These PRs have been open for over a year due to this issue:

• Closes Update terraform-module-versions to 3.1.14 #3029
• Closes Update rakkess to 0.5.1 #3084