There's a difference between using an API and reimplementing one. Nobody's saying that you can get in copyright trouble for using an API. And to my knowledge, Go(lang) doesn't have the "embed in an electronic device" restriction that Java had.
If you tried to create a different implementation of Go that used the same API, whether you could get in trouble depends on Google's license. And then, if the license is against you, whether you do get in trouble would be at Google's discretion.
Note well: IANAL. Also, I'm still hoping that this "copyrighting the API" will be overturned at the Supreme Court, in which case this whole conversation is moot.
If you tried to create a different implementation of Go that used the same API, whether you could get in trouble depends on Google's license. And then, if the license is against you, whether you do get in trouble would be at Google's discretion.
Note well: IANAL. Also, I'm still hoping that this "copyrighting the API" will be overturned at the Supreme Court, in which case this whole conversation is moot.