Add retry logic before download asset from github (#5181)
Add retry logic before download asset from github (#5181)

The docker release fails when released binaries are not available for download immediately after the release is created.
This PR adds retry logic (up to 10 min).

Signed-off-by: Yong Tang <765086fe2e0c1f980161f127fec596800f327f62@outlook.com>
coredns/coredns,chrisohaver/coredns,yongtang/coredns