chore: update cockroachdb-skills submodule (9 new commits)

[github-actions]

Updates cockroachdb-skills submodule from 8716a6593b7ef577e17d87c4d196ba18d9349c52 to 9e73c9d45894449490c23ce90d18e6f233251dfa.

Upstream changes

9e73c9d Merge pull request #13 from cockroachlabs/add-skill/security-and-governance/auditing-cis-benchmark
52b665f Remove compliance context question from Step 0
e0f673c Fix #4: Remove duplicate H1 heading in sample report
4d764d5 Fix #2: Rename 5.1/5.2 header to 5.1 only; Fix #3: Align 3.3 eventlog query with cis-controls.md
bdd811b Fix #1: Clarify 1.5 uses cockroach version (quick scan) and gossip_nodes (full audit)
0279162 Add sample CIS benchmark audit report
8725ad6 Add SQL queries reference for CIS benchmark audit
6034ac7 Add CIS controls reference with Quick Scan and Full Audit procedures
4584608 Add auditing-cis-benchmark skill

This PR was auto-generated by the update-skills workflow.