[Spec] Correctly specify authenticatorSelection requirements

[stephenmcgruer]

These were previously incorrect specified as auth-time requirements, but they
are actually registration time arguments. This was overlooked as the build
action didn't fail on warnings by default. This commit also changes the action
to fail in such cases.

Fixes #129

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Preview | Diff

[stephenmcgruer]

(Still a draft as the actual links aren't fixed yet; testing that the build change actually fails the build)

[ianbjacobs]

Hi @stephenmcgruer,
It seems you removed some text we had previously added about residentKey and authenticatorAttachment. Was that intentional?

[stephenmcgruer]

@rsolomakhin @ianbjacobs - residentKey and authenticatorAttachment are not auth-time arguments for WebAuthn. I suspect what you were trying to do was to record that Chrome's current implementation requires residentKey="required" and authenticatorAttachment="platform" at registration time - is that correct? Assuming so, that actually needs to go in the registration steps - I can do that in this CL too.

[ianbjacobs]

@stephenmcgruer,
+1 to doing any clarifications you deem helpful. Moving the info to another part of the spec seems fine. Thank you.

[stephenmcgruer]

@rsolomakhin @ianbjacobs - properly specified the limitations, please take a look. Rouslan, please double-check I've listed these correctly.

[rsolomakhin]

This is correct. Thank you!