The build was on bookworm. 0.12.0 was built on bookworm too.

I rebuilt on Bullseye and uploaded to the github release, just for you:

83a56f2dfe62aaf019d30806c29651da9c79c61e109599d09eb648121518a051 gossip_0.13.0-1_amd64.bullseye.deb