I've noticed that truncated versioning upgrades is no longer working.

Looking at the logs in Renovate, the versions are reporting as invalid:

```json
 {
  "depName": "goreleaser/goreleaser",
  "currentValue": "2.3",
  "datasource": "github-releases",
  "versioning": "semver",
  "replaceString": " 2.3 # datasource=github-releases depName=goreleaser/goreleaser\n",
  "updates": [],
  "packageName": "goreleaser/goreleaser",
  "warnings": [],
  "skipReason": "invalid-value"
}
```

This is an attempt to fix this situation by switching to coerced semver,
which allows coersion of truncated version numbers

Now that we manage our own goreleaser container images, it's more
straight-forward to publish truncated version tags.

This will further reduce the number of Renovate MRs.

An attempt to work around #26

Part of https://gitlab.com/gitlab-com/gl-infra/common-ci-tasks/-/issues/19

This adds some documentation on how to publish truncated versions for
Kaniko images and Goreleaser.

Part of https://gitlab.com/gitlab-com/gl-infra/common-ci-tasks/-/issues/19

Adds a preset to allow Renovate to Truncate Versions for certain known
dependencies.