Create SECURITY.md

[Abuchtela]

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Fill out the following table describing your edits:

Original	Updated	Change	Reasoning
3237745	3237938	Remove sandwich traders using dex.sandwiches	We should only care about traders who are not doing MEV
evm_grants.csv	n/a	added grants for Optimism	captures approved grants only

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Note to Contributor:

Make sure your PR edits the original query_id.sql file with the new query text. If you are proposing adding a new query completely, make sure to add it to queries.yml and as a file in /queries as well.

Thanks for contributing! 🙏