Update Go image to 1.20

With the release of Go 1.21, scheduled for August, we should update the base Go image to 1.20

added P3 label

assigned to @eigenwijsje

changed milestone to %1.0-alpha3 — Playful Platypus

added 1 deleted label

added To Do label

added Doing label and removed To Do label

mentioned in commit 3b6a8048

closed

removed Doing label