Updating crates.io index
    Updating git repository `https://github.com/felixonmars/ring`
warning: spurious network error (2 tries remaining): failed to resolve address for github.com: No address associated with hostname; class=Net (12)
warning: spurious network error (1 tries remaining): failed to resolve address for github.com: No address associated with hostname; class=Net (12)
error: failed to resolve patches for `https://github.com/rust-lang/crates.io-index`

Caused by:
  failed to load source for dependency `ring`

Caused by:
  Unable to update https://github.com/felixonmars/ring?branch=0.16.20

Caused by:
  failed to clone into: /build/.cargo/git/db/ring-9d9b612f6fc19bae

Caused by:
  network failure seems to have happened
  if a proxy or similar is necessary `net.git-fetch-with-cli` may help here
  https://doc.rust-lang.org/cargo/reference/config.html#netgit-fetch-with-cli

Caused by:
  failed to resolve address for github.com: No address associated with hostname; class=Net (12)
==> ERROR: A failure occurred in prepare().
    Aborting...