Improve test pipeline

What's Changed

• Inherit go version from go.mod file by @jeffwidman in #615
• Default to the go version in go.mod by @jeffwidman in #618
• Remove versioning disclaimer by @ErikPelli in #619
• Pre-emptively prevent test fixtures from lingering global state by @jeffwidman in #616
• Enable race conditions detector by @ErikPelli in #620

New Contributors

• @jeffwidman made their first contribution in #615

Full Changelog: v1.2.7...v1.2.8