Indicate lack of plans to add SafetyNet support

[Firehed]

Google has deprecated SafetyNet attestation format. Since this library already does not offer support for verifying it, this clarifies that there are now no plans to do so.

android-key support should still get added, and the verification procedure is quite a bit more straightforward, though I've still yet to track down a test vector or obtain a device that produces this format.

https://android-developers.googleblog.com/2024/09/attestation-format-change-for-android-fido2-api.html

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.36%. Comparing base (1c7b416) to head (80bc7cc).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main      #87   +/-   ##
=========================================
  Coverage     81.36%   81.36%           
  Complexity      308      308           
=========================================
  Files            33       33           
  Lines           982      982           
=========================================
  Hits            799      799           
  Misses          183      183           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.