Fix README tag pollution from update script

[fank]

Summary

This PR fixes the issue where the update script was polluting the README with too many duplicate and outdated tags.

Problem

The current update.sh script lists ALL versions from buildinfo.json in the README, resulting in:

• 60+ lines of tags
• Multiple duplicate major.minor version tags (e.g., 2.0 appearing on many lines)
• Old stable tags that are no longer relevant

Solution

Modified the tag generation logic in update.sh to:

1. Show only the latest experimental version with its tags
2. Show only the current stable version with its tags
3. Fixed the jq query to properly detect stable version using index() instead of contains()
4. Removed the logic that was creating duplicate entries for each version

Result

Before: 60+ lines of tags with many duplicates
After: 2 clean lines showing only the most relevant tags:

* `latest, 2.0.58`
* `2, 2.0, 2.0.55, stable, stable-2.0.55`

This makes the README much cleaner and easier to read while still providing all the essential tag information users need.

Testing

• Tested the tag generation logic separately to ensure it produces the correct output
• Verified that the script correctly identifies the latest and stable versions
• Confirmed the README is updated with the new clean format