[mediacapture-main] new commits pushed by alvestrand

The following commits were just pushed by alvestrand to https://github.com/w3c/mediacapture-main:

* Remove outdated mentions of Media Capture Task Force

Spec now fully owned by WebRTC
Also, point to github repo rather than mailing list
  by Dominique Hazael-Massieux
https://github.com/w3c/mediacapture-main/commit/5230d6d6758ab5bf699bae59b39c6f679690ee8e

* Merge pull request #681 from w3c/no-media-capture-tf

Remove outdated mentions of Media Capture Task Force
  by Harald Alvestrand
https://github.com/w3c/mediacapture-main/commit/be0c92757b49169fe7372415e52189f5734c5a54