Update rust deps

[tjkirch]

commit 39444f6f4d553091045e2073b26a5077f563cf42
Author: Tom Kirchner <[email protected]>
Date:   Wed Dec 18 15:40:15 2019 -0800

    Update minor versions of Rust deps with trivial/no changes

commit dfa8cda0ec2de6e3f6e7153543a9058c0938949e
Author: Tom Kirchner <[email protected]>
Date:   Wed Dec 18 15:21:58 2019 -0800

    Update snafu to 0.6

commit 25708b68602678b41d2ba77000cd3972333a4de9
Author: Tom Kirchner <[email protected]>
Date:   Wed Dec 18 15:18:14 2019 -0800

    `cargo update` workspaces/ dependencies

commit 1490a48b1c3763d4a686bb70548cb7ac0b527ec3
Author: Tom Kirchner <[email protected]>
Date:   Wed Dec 18 15:17:30 2019 -0800

    Update dependencies of buildsys

commit 763ee5c9208364f77bcdaec09d9a428909b9e416
Author: Tom Kirchner <[email protected]>
Date:   Wed Dec 18 15:17:18 2019 -0800

    Update dependencies of repo canary

---

Might help to look at the individual commits.

Implementation notes:

• Not updating futures/hyper/tokio until async changes have stabilized a bit.
• Can't update http until new actix is out.

Testing done:

Tested that canary still works, it validated all targets.

Built an aws-k8s AMI, it connected to my cluster and ran a pod OK, systemctl status running, things seem OK. Built an aws-dev AMI, it ran a Docker container OK, systemctl status running, things seem OK.

[tjkirch]

(Fixed typo "workspacess" in commit message)

[tjkirch]

(Fixed base branch now that related PRs are merged)