Fix docker compose warning regarding the version field

[XSAM]

Fix this warning:

WARN[0000] otelsql/example/otel-collector/docker-compose.yaml: `version` is obsolete

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.1%. Comparing base (2e34895) to head (81c68de).

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #255   +/-   ##
=====================================
  Coverage   84.1%   84.1%           
=====================================
  Files         13      13           
  Lines        605     605           
=====================================
  Hits         509     509           
  Misses        72      72           
  Partials      24      24           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.