go -> 1.21 and bump mysql driver

[muir]

The new mysql driver needs go 1.21

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.72%. Comparing base (622b7fb) to head (13a617e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #229   +/-   ##
=======================================
  Coverage   77.72%   77.72%           
=======================================
  Files          12       12           
  Lines        1257     1257           
=======================================
  Hits          977      977           
  Misses        204      204           
  Partials       76       76           

Flag	Coverage Δ
go_tests	9.14% <ø> (ø)
mysql_tests	51.09% <ø> (ø)
pg_tests	50.97% <ø> (ø)
singlestore_tests	46.52% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.