Disable cgo goreleaser

[zkauker]

fix to close issue #48

[zkauker]

@zambien I've tested this by building the provider binaries in ubuntu docker image (to simulate travis env) as follows:

1. I built a provider with the previous goreleaser config
2. I built an other binary with the new config
3. In a hasicorp/terraform:light container I tried to use the binary built in step 1. - failed the same way as it fails with the official builds
4. In the same container I tried to use the binary built in step 2. - worked without w/o any issues

So if you find this OK would you mind to cook another crispy release?

[zambien]

Yep, you got it.