docker-compose.search.yml: Upgrade elasticsearch container
Upgrade elasticsearch container to 7.9.3 (matches the current version deployed on staging and soon to be for production)
7.10.1 which fixes T2871 is not yet released.
Related to swh-search#2791 (closed)
Test Plan
doco -f docker-compose.yml -f docker-compose.search.yml up
happy
Migrated from D4703 (view on Phabricator)