ci: add dependabot

[ararog]

I'm having some trouble trying to compile my project on macos since future-tls uses an outdated version of ring. This PR add dependabot support to the project, allowing to keep dependencies updated and free of potential security issues with outdated deps.

@djc @quininer please let me know if I can help on keep this crate updated.

[djc]

Thanks for the ping -- this project indeed has been pretty dormant.

Not sure how this PR helps you figure out how to compile your project on macOS -- do you have an error message? It usually just works for me. What version of futures-rustls are you using, anyway?

I didn't like some of the things in your PR and decided it would be faster to redo it to match the style we usually use for rustls projects. Submitted that as

• Updates #16

[ararog]

@djc thanks for take a look in this.

I decided to use futures-rustls in my projects since most of them supports both tokio and smol, maybe compio soon.

In the end, I managed to fix the issue, this has some relation with ring version, and in fact futures-rustls is free of this assertion error on mac arm.

Anyway, keep this crate deps updated will be very helpful, thanks!