Support UPDATE SQL statement

[nagakrishna]

Describe the solution you'd like
Query bench feature with SQL support is a great. But it currently lacks support for UPDATE sql statement. Our team is looking use builtin functionalities of OpenSearch like Dashboard's and provide it as an interface to our customers to manipulate data.

Describe alternatives you've considered
Using DSL to update the records, but it requires _id (opensearch metadata fields) which is currently not possible to retrieve through SQL query #1038

[dai-chen]

Thanks for reporting the issue! This enhancement was tracked in opendistro-for-elasticsearch/sql#1038. We will evaluate it and see if we can prioritize.