I was curious as to the current state of EE3 for 1.9.4, so I decided to clone the branch and try to build it, but when I run setupDecompWorkspace, I'm getting this error. I'm not too versed in all this maven/gradle stuff, so I'm not quite sure how to fix it. Help is appreciated.

Just keep rerunning the command. This is not an EE3 related issue.