Ver.0.4.0

What's Changed

• fix: update installation instructions in README.md and README_JA.md by @kochounoyume in #33
• ci: Update CI by @kochounoyume in #34
• ci: Update unity-test.yml by @kochounoyume in #35
• Feature/update editorconfig2 by @kochounoyume in #36
• ci: Create publish-nuget.yml by @kochounoyume in #37
• fix: README with NuGet by @kochounoyume in #38
• Feature/update editorconfig2 by @kochounoyume in #39
• Feature/update editorconfig2 by @kochounoyume in #40
• Feature/refactor idb by @kochounoyume in #42
• chore: bump version to 0.4.0 by @github-actions[bot] in #43

Full Changelog: 0.3.4...0.4.0