On your build system you need an up to date go compiler. Create an executable like this
$ go build -o /tmp/nctalkproxyd cmd/nctalkproxyd/main.go
The source code does provide a bash-script to create an OCI format based image. OCI image do allow installation as rootless package
$ bash -x ./build_container.sh
Get the container-id to be uploaded:
$ imageid=$(buildah image | grep $botname | awk -F " " '{ print $3 }')
Tag the container to an image:
$ buildah commit $imageid quay.io/username/$botname:latest
Now login to Quay.io:
% podman login quay.io
Finally upload:
$ buildah push quay.io/username/$botname:latest