fix(ci): Handle shallow clones in release script

[pando85]

Summary

• Add ensure_full_history() function to .ci/release.sh that detects shallow clones (e.g. CI with fetch-depth: 1) and automatically fetches full history and tags
• This prevents CHANGELOG generation failures when git-cliff or other tools need full commit history
• Update RELEASE.md to document what the release script does automatically

Changes

• .ci/release.sh: Added ensure_full_history function that unshallows repos and fetches tags before any git operations
• RELEASE.md: Added documentation of script's automatic steps including shallow clone handling

Same fix pattern as applied in forkline/ingress-nginx repo.

[forkline-bot]

Analysis Complete

After thorough investigation, PR #358 has NO merge conflicts:

Evidence:

• GitHub API reports: "mergeable": true, "conflicts": false
• Local merge test: Already up to date
• Master has no new commits (both branches share commit 696aeab)
• PR branch is one commit ahead of master (e07fc54)
• Branch sync: Everything up-to-date

PR Status:

mergeable: true
conflicts: false
ci_passed: false
reviews_approved: false

The PR is correctly based on the latest master commit with no conflicts. It's not ready to merge because CI hasn't passed and there are no approved reviews, but there are no merge conflicts to resolve.