v4.2.9: HCAL veto default, inverse skimming, CI improvements

Cutting a release for two reasons: testing the CI that failed when 4.2.8 was built, and #1564 changed golds

⚡ Highlights

• Change HCAL veto default to 8 by @tvami in #1564
• Inverse skimming in vetos by @tvami in #1563
• Add comment based PR validation by @tvami in #1556
• Add comment if manually trigger workflow by @tvami in #1558

🐛 Fixes

• include VERSION in ldmx-sw package for PR validation by @tomeichlersmith in #1554

🤖 Bot

• New Gold for Generated by release 4.2.8 by @github-actions in #1550

Full Changelog: 4.2.8...v4.2.9