Remove deprecated "$COMPLETE" variable from version template for release drafter workflow

[cheeseandcereal]

Description

Fix: Remove the version-template override. The release-drafter v7 default is $MAJOR.$MINOR.$PATCH$PRERELEASE, which matches the old v6 $COMPLETE behavior for stable releases and also keeps any future prerelease (-rc.N) rendering correct. An equivalent valid override version-template: '$MAJOR.$MINOR.$PATCH' would also work, but dropping the override is cleaner.

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the userdocs directory)
• Manually tested
• Made sure the title of the PR is a good description that can go into the release notes
• (Core team) Added labels for change area (e.g. area/nodegroup) and kind (e.g. kind/improvement)

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[github-actions]

Hello cheeseandcereal 👋 Thank you for opening a Pull Request in eksctl project. The team will review the Pull Request and aim to respond within 1-10 business days. Meanwhile, please read about the Contribution and Code of Conduct guidelines here. You can find out more information about eksctl on our website