Bug#1028222: Don't release for bookworm

[Shengjing Zhu]

Source: golang-1.20
Version: 1.20~rc2-1
Severity: serious
X-Debbugs-Cc: z...@debian.org
Control: clone -1 -2
Control: reassign -2 src:golang-1.18 1.18.9-1

Usually we only keep one go compiler in stable. For bookworm it should be
golang-1.19.