v0.2.1

Changelog

• ef91dcc Bump version
• 0629218 Change 'like', set 'green' as whole foreign words
• 64c35e5 Optimize tree traversal function
• 5f35172 Recognize one more character for fixing the punctuation
• 1633793 Update README.md
• 762b960 Update README.md
• b810e99 Update and rename LICENSE to LICENSE.md
• 3656be3 Update release.yml