New Fixed Income latest prices and quotes endpoints

Market Data API

Adds Fixed Income market data endpoints:

• GET /v1beta1/fixed_income/latest/prices returns the latest prices, backed by the new fixed_income_price and fixed_income_latest_prices_resp schemas.
• GET /v1beta1/fixed_income/latest/quotes returns the latest quotes, backed by the new fixed_income_quote and fixed_income_latest_quotes_resp schemas.

A Fixed income tag is now available, and Fixed Income is listed among the supported market data APIs.

Affected Endpoints

• GET /v1beta1/fixed_income/latest/prices
• GET /v1beta1/fixed_income/latest/quotes