`install.sh` not found

When I run:

curl -fsSL https://atcr.io/install.sh

I get:

curl: (22) The requested URL returned error: 404

I can't install it with:

go install atcr.io/cmd/credential-helper@latest

because I get this error:

go: atcr.io/cmd/credential-helper@v0.1.2: unrecognized import path "atcr.io/cmd/credential-helper": reading https://atcr.io/cmd/credential-helper?go-get=1: 404 Not Found