- add `go-modules` for automated creation of go vendored modules tarball
- bump go version: `BuildRequires: golang(API) >= 1.23`
- delete unused `kube-flannel.yaml` source in the spec file, it is directly soured from the flannel source tar ball
OBS-URL: https://build.opensuse.org/package/show/devel:kubic/flannel?expand=0&rev=18