docs: change guava example from regex manager to extractVersion

[rarkins]

Related discussion below:

Discussed in #29826

^{Originally posted by ipletnjov-tw June 24, 2024}

What would you like help with?

I think I found a bug

How are you running Renovate?

Self-hosted

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

GitHub, version 37.415.0

Please tell us more about your question or problem

Reproduction repository: https://github.com/ipletnjov-tw/renovate-guava-osv-config-issue

A Java (Maven) repository containing an outdated Guava version combined with "osvVulnerabilityAlerts": true and a packageRule with "versioning": "regex:^(?<major>\\d+)(\\.(?<minor>\\d+))?(\\.(?<patch>\\d+))?(-(?<compatibility>.*))?$" for the Guava package will result in a "Action Required: Fix Renovate Configuration" issue being created by Renovate.

Example from the repro repo:

• Configure Renovate - autoclosed ipletnjov-tw/renovate-guava-osv-config-issue#1
  (Part of the onboarding PR for some reason, instead of an issue)

The regex versioning string above was taken directly from Renovate docs on regex versioning:
https://github.com/renovatebot/renovate/blob/main/lib/modules/versioning/regex/readme.md?plain=1#L21

This seems to be a regression caused by #29666, as running Renovate version 37.408.1 auto-closed the "Action Required: Fix Renovate Configuration" issue in our repos and our PRs were updated as usual.

Logs (if relevant)

Logs

Let me know if the repro repo isn't enough and I'll try and get my hands on the debug logs.