OKF Workbench 0.3.0

What's Changed

• docs: record 0.2.1 publication by @koizumikento in #43
• Add OKF v0.2 support with v0.1 fallback by @koizumikento in #44
• Add assisted OKF v0.2 migration by @koizumikento in #45
• Prepare OKF Workbench 0.3.0 release by @koizumikento in #48
• Fix Windows atomic publication for 0.3.0 by @koizumikento in #49
• Fix Windows staging publication on native handles by @koizumikento in #50
• docs: record 0.3.0 release qualification by @koizumikento in #51

Full Changelog: v0.2.1...v0.3.0