Extension not supported for OAuthFlow

[mathis-m]

It should be possible to provide extension x-tokenName to an oAuthFlow:

eg:

@SecurityScheme(
        type = SecuritySchemeType.OAUTH2,
        flows = @OAuthFlows(
                authorizationCode = @OAuthFlow(
                        authorizationUrl = "https://accounts.google.com/o/oauth2/auth",
                        tokenUrl = "https://oauth2.googleapis.com/token",
                        extensions= @Extensions({
                                @Extension(name = "x-tokenName", value = "id_token")
                        }),
                        scopes = {
                                @OAuthScope(
                                        name = "openid"
                                ),
                                @OAuthScope(
                                        name = "profile"
                                ),
                                @OAuthScope(
                                        name = "email"
                                )
                        }
                )
        )
),

[MikeEdgar]

+1, but closing as a duplicate of #387. Please re-open if you disagree.