Fix typo in goarch file

Author: gnufied

hack/build-go.sh

@@ -9,7 +9,7 @@ GLDFLAGS=${GLDFLAGS:-}
 eval $(go env | grep -e "GOHOSTOS" -e "GOHOSTARCH")
 
 GOOS=${GOOS:-${GOHOSTOS}}
-GOARCH=${GOACH:-${GOHOSTARCH}}
+GOARCH=${GOARCH:-${GOHOSTARCH}}
 
 # Go to the root of the repo
 cd "$(git rev-parse --show-cdup)"