Deduplicate base64

[nox]

Latest release is 0.12, brought in crate tree through #26005.

Dependencies that already depend on 0.12 that we need to bump on our side:

• headers
  • warp
  • hyper_serde

Dependencies on 0.10 that Mozilla people maintain:

• webdriver (depends on warp)
• webrender

Dependencies on 0.10 that require upstream changes:

• influent

Dependencies on 0.11 that require upstream changes:

• rust-argon2
  • redox_users

[Eijebong]

For info: webdriver -> https://bugzilla.mozilla.org/show_bug.cgi?id=1606281

[Eijebong]

Also I just published influent 0.5.3 with base64 0.12

[Eijebong]

Influent will also need an update for tokio. Is it really something useful for servo ? I'm currently kind of maintaining for dep updates but I don't have any real motivation to do so.