fix(renovate): keep chart majors out of the FerrLabs charts group

[BryanFRD]

Summary

• Follow-up to chore(renovate): let FerrLabs charts through without the one-day wait #354, addressing the review nit. The FerrLabs charts rule had no matchUpdateTypes, so majors joined the group. Grouping ignores the major/minor split, and generateBranchConfig turns the branch's automerge off as soon as one upgrade in it carries automerge: false — which the last rule of the file gives majors. A pending chart major would therefore have blocked the very patch and minor bumps the rule exists to fast-track.
• Restricted to patch and minor. A major now falls through to the global one-day age and stays an ungrouped manual PR, which is the behaviour it had before chore(renovate): let FerrLabs charts through without the one-day wait #354.

Test plan

• default.json parses, diff is the four added lines plus the reworded description
• Next Renovate run still fast-tracks a FerrLabs chart patch/minor, and a chart major appears as its own manual PR

[ferrfleet]

Checked against the full default.json at head: with matchUpdateTypes: ["patch", "minor"] the org charts rule no longer applies groupName, minimumReleaseAge: 0 or automerge: true to a major. The preceding Kubernetes infra rule is patch/minor-only too, so a chart major is not re-captured there either and lands on the global one-day age plus the final major / automerge: false rule, as the description states. The branch-level automerge collapse this fixes matches generateBranchConfig behaviour.

Nothing blocking.