coreos-metadata v3.0.0

Bugfixes:

• providers/gcp: scrape new endpoint for ssh keys (#112, thanks @andor44!)

Misc:

• cargo: bump update-ssh-keys to 0.3.0 (#114)
• src: make a single-binary only project (#113)

This project is now available on the public crates.io registry: https://crates.io/crates/coreos-metadata