Add retries for 502, 504 HTTP statuses

Add 502 Bad Gateway and 504 Gateway Timeout HTTP status to client's retry logic

Add tests for retries on 502,504 and test that no retry is done on another status (404)

Add support for forwarding OAuth2 authorization header

Allow calling out breaking changes in releases

Support EXECUTE IMMEDIATE

Use EXECUTE IMMEDIATE sent in the HTTP request body, instead of putting
the query text in HTTP headers. This should allow sending large query
text. It can be enabled by setting the `explicitPrepare` option to
false in the connection string.

Update dependencies

Don't fail when decoding empty strings as floats in server responses

Release v0.314.0

Support nil query parameters

Use default CAs if neither cert or cert path is provided