Revert "Use ubuntu 20.04 for release builds (#12202)"

[mattlord]

Description

The underlying issue has now been addressed in: #12214

Related Issue(s)

• Related to: Releases: VTOrc Unusable on Many Linux Platforms #12185
• Follow-up to: Move vtorc from go-sqlite3 to modernc.org/sqlite #12214

Checklist

• "Backport to:" labels have been added if this change should be back-ported
• Tests re not required
• Documentation is not required

[vitess-bot]

Review Checklist

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