On the screenshot, it shows that 4 engines detected two possibel threats. But as they are not specific my guess is that their "behaviour" analyzer said "maybe" (threat detectors will rather lean to the negative side so that, if its actually a legit threat, no one can blame them).
But in the end, you only have two options: thrust in gogs ability to keep their domain from beeing hijacked and their servers from beeing compromised. Or you create a ticket in the support system, probably leading to a "we checked everything seems to be alright" message by monday (probably not much happening over the weekend, especially in a very catholic country like Poland)
Your choice, my suggestion: As there is no specific threat mentioned: install it