The v3.x/staging branch cannot be successfully built by the Build workflow, which means no new v3 package can be created.
I spent quite a lot of time on trying to fix it in my laptop but did not succeed, as I am not a web GUI dev, so I am adding this issue here --- maybe the it is pretty simple for experienced frontend devs, so she/he could fix it in a blink of an eye.
Finger crossed.