[v0.5.0] Avoid leaking timeout timer channels and update github actions

What's Changed

• remove empty go.sum by @thaJeztah in #100
• gha: update actions and go versions by @thaJeztah in #102
• Avoid leaking goroutines on close by @liggitt in #101

Full Changelog: v0.4.0...v0.5.0