add a retry in case we get a 5xx error from github
add a retry in case we get a 5xx error from github

[finish #140129751]

Signed-off-by: Alex Melnik <d8d38b2b5e79d5bbc1987e042c4cf1e377fad8e2@suse.com>

cloudfoundry-incubator/cli-plugin-repo,guidowb/cli-plugin-repo,kkellner/cli-plugin-repo,guidowb/cli-plugin-repo,cloudfoundry-incubator/cli-plugin-repo,kkellner/cli-plugin-repo,cloudfoundry-incubator/cli-plugin-repo,cloudfoundry-incubator/cli-plugin-repo,guidowb/cli-plugin-repo,kkellner/cli-plugin-repo,guidowb/cli-plugin-repo