feat: checking kb header value

[lukasjhan]

I added checking logic of header of key binding JWT.

I referenced from standard:

8.3. Verification by the Verifier
3. Ensure that a signing algorithm was used that was deemede public key for the Holder from the SD-JWT
secure for the application. Refer to [RFC8725], Sections 3.1
and 3.2 for details. The none algorithm MUST NOT be accepted
5. Check that the typ of the Key Binding JWT is kb+jwt.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.43%. Comparing base (38ffb3c) to head (26df50c).

Additional details and impacted files

@@            Coverage Diff             @@
##             next     #133      +/-   ##
==========================================
+ Coverage   97.41%   97.43%   +0.01%     
==========================================
  Files          23       23              
  Lines        1899     1908       +9     
  Branches      273      279       +6     
==========================================
+ Hits         1850     1859       +9     
  Misses         49       49              

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[berendsliedrecht]

Fine for now, but I think having an assertHeaderClaim method will help a lot here to make the code more readable and we can also return messages that tell the user on which property it failed.

like this: https://github.com/berendsliedrecht/sd-jwt-ts/blob/a1fb5fad0b938081e033233bae5569ae3b9fe8cb/packages/core/src/sdJwtVc/sdJwtVc.ts#L41

[lukasjhan]

Oh, That's good idea.