v6.21.0

What's changed

🎉 Features

• feat: support tilingMode: cog for raster data type to allow visualization from external stac (#1982)

🐛 Fixes

• fix: make variables a repeat query params instead of comma separated (#1987)

🚀 Improvements

• chore: disable auto-release, add maintenance mode notice (#1988)
• ci: disable scheduled auto-release, rename workflow to Release
• docs: update RELEASE.md for manual-only releases
• docs: add maintenance mode banner to README