update to cargo 0.63/git2 0.14

the main change seems to be that registries no longer have an explicit update() call, but instead return Poll on queries with a helper to block until the Poll is ready.

upstream change for reference: https://github.com/rust-lang/cargo/pull/10064

only build-tested so far. there might be other changes required as well to accomodate namespaced features and weak dependencies.

Signed-off-by: Fabian Grünbichler f.gruenbichler@proxmox.com