Use init-release task to generate goreleaser file

[apoorvam]

Instead of hardcoding goreleaser config file, using goreleaser init command in another dunner task to generate this file.

So user can do:

dunner init go-github-release # init recipe
dunner do init-release # generates goreleaser config file
dunner do go-github-release # make release

[apoorvam]

This dunner task gives an error as:

OCI runtime exec failed: exec failed: container_linux.go:344: starting container process caused "process_linux.go:91: executing setns process caused \"exit status 21\"": unknown

Working on this.