Go images based off of Debian `bullseye` no longer maintained

[atc0005]

Overview

Debian bullseye is no longer supported as of August 12 when the docker-library/golang repo merged PR 564 to add Debian Trixie and drop Debian Bullseye from their build process.

We'll need to replace all references in active images for bullseye with bookworm for consistency.

This currently affects 6 Dockerfiles:

• oldstable/build/cgo-mingw-w64-x64/Dockerfile
• oldstable/build/cgo-mingw-w64-x86/Dockerfile
• stable/build/cgo-mingw-w64-x64/Dockerfile
• stable/build/cgo-mingw-w64-x86/Dockerfile
• unstable/build/cgo-mingw-w64-x64/Dockerfile
• unstable/build/cgo-mingw-w64-x86/Dockerfile

References

• Add Debian Trixie (drop Bullseye) docker-library/golang#564