feat: Adds flag to optionally use system certificates when fetching latest release.

[mchernicoff]

Resolves #132 See that issue for details.

This adds the "native" flag to the axoupdater CLI. If this flag is set, axoupdater will fetch the latest release using native system certs for TLS, instead of the reqwest crate's default Mozilla WebPKI certs.

[mchernicoff]

This patch has not been fully tested in a production-like environment. In order to test it, a new release of axoupdater must first be created with these changes. Then you should run cargo dist build with cargo-dist with the updater option enabled to install axoupdater, then check that the newly created update command correctly allows the use of the "native" flag.

[mistydemeo]

Apologies for the delay on reviewing here.

This makes sense to me conceptually, but I'm wondering a bit about the usability. In what circumstances would a user know that they need to pass the --native flag? Is this something that users in your environment are going to pass explicitly, or a default that all users using your distributed software will need? If it's the latter, I wonder if it would be better to have the CLI gate this based on environment variables.