Debian Rules to copy build file

🧩 Syntax:
%:
        dh $@ --builddirectory=_build --buildsystem=golang --with=golang

execute_before_dh_auto_build:
        mkdir -p _build/src/github.com/cilium/ebpf/cmd/bpf2go
        cp cmd/bpf2go/output.tpl _build/src/github.com/cilium/ebpf/cmd/bpf2go/output.tpl