Use OAuthAuthorizationServerOptions.SystemClock and favor AuthenticationProperties.ExpiresUtc when present
Make OpenIdConnectServerOptions.SigningCredentials mandatory to avoid NRE in OpenIdConnectServerExtensions.CreateIdToken
Distinct IssuedUtc, IdTokenIssuedUtc, ExpiresUtc and IdTokenExpiresUtc
Merge pull request #2 from PinpointTownes/dev

Use SystemClock, favor ExpiresUtc when present and make SigningCredentials mandatory