PSA: TLS 1.0 deprecation - will happen again in M82

[Harald Alvestrand]

Following our rollback of TLS 1.0/DTLS 1.0/TLS 1.1 removal in M76, we've added a deprecation notice in M80, and have started observing usage numbers; these usage numbers are quite encouraging (low).

We plan to remove those protocol versions permanently in Chrome M82.

People who see serious hardship with this schedule probably need to start preparing soon; the bug to follow is https://crbug.com/webrtc/10261

For background on why the removal is necessary, see the Google security blog:  https://security.googleblog.com/2018/10/modernizing-transport-security.html

Harald