[ftl-build] v2.5.1

What's Changed

• Bump actions/upload-artifact from 3 to 4 by @dependabot in #91
• Bump docker/metadata-action from 4 to 5 by @dependabot in #92
• Bump Chizkiyahu/delete-untagged-ghcr-action from 3 to 4 by @dependabot in #93

The reason for building this new image is that we want to get an up-to-date ftl-build image after the gmp bug has been fixed about an hour ago.

Full Changelog: v2.5...v2.5.1