[Buttons] Border-radius should be 4px

[IlCallo]

Bug, feature request, or proposal:

Bug

What is the expected behavior?

As written in the specs, border-radius should be 4px instead of the old 2px value (in the specs they're expressed in dp but I guess it's a 1-to-1 conversion)

What is the current behavior?

They have 2px border-radius

Which versions of Angular, Material, OS, TypeScript, browsers are affected?

Angular 6.0.6
Material 6.3.1

Is there anything else we should know?

This can probably be addressed directly on the new #11961 base class for buttons

[crisbeto]

We're still running against the previous version of the Material design spec. We'll start implementing the new version soon.

[IlCallo]

Oh, ok. Shall I close the issue or leave it open?

[crisbeto]

Let's close it so the info doesn't get scattered. We'll probably have an issue for tracking all the changes when we get to it.

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