Add support for requestedAccessTokenVersion:null access tokens (iss sts.windows.net)

[aleksandr-vin]

Closes #214

Adds support for v1 access tokens, those with "iss": "https://sts.windows.net/...../".

Example to use would be:

azure_scheme = SingleTenantAzureAuthorizationCodeBearer(
    app_client_id=settings.APP_CLIENT_ID,
    tenant_id=settings.TENANT_ID,
    scopes=settings.SCOPES,
    access_token_version_one=True,
    audience=f"https://{settings.APP_CLIENT_ID}.my.fancy.service.io",
)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.0%. Comparing base (2256921) to head (bc47fab).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #215   +/-   ##
=======================================
  Coverage   100.0%   100.0%           
=======================================
  Files           6        6           
  Lines         267      268    +1     
=======================================
+ Hits          267      268    +1     

Files with missing lines	Coverage Δ
fastapi_azure_auth/auth.py	100.0% <100.0%> (ø)

[JonasKs]

Hi,

I'm sorry, but I don't really want to support v1 tokens as Microsoft has retired them in 2022, and recommended everyone to upgrade. Link

I had token support before #200(but removed to keep this library as simple and maintainable as possible), so if you really need it, I'd recommend to either use your fork, use v4, or override this in your own app.