chore: add conventional commits. fix #230

.github/CONTRIBUTING.md

@@ -0,0 +1,19 @@
+# Contributing Guide
+
+Thanks for lending a hand 👋
+
+Here are a few ways to contribute:
+
+- [Add a theme](./docs/themes.md#adding-theme)
+- [Add a language grammar](./docs/languages.md#adding-grammar)
+- Fix a bug
+
+## Coding conventions
+
+- We use [prettier](https://prettier.io). Before you commit, all files will be formatted automatically.
+- We use [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/). Please use a prefix. If your PR has multiple commits and some of them don't follow the Conventional Commits rule, we'll do a squash merge.
+
+## Fix a bug
+
+- Reference the bug you are fixing in the PR
+- Add a test if possible

.github/pull_request_template.md

@@ -1,3 +1,6 @@
+- [ ] Add a test if possible
+- [ ] Format all commit messages with [Conventional Commits](https://www.conventionalcommits.org/en/v1.0.0/)
+
 <!-- If fixing a bug -->
 
 - [ ] This PR fixes #

README.md

@@ -65,8 +65,7 @@ Clone [shikijs/shiki-starter](https://github.com/shikijs/shiki-starter) to play
 
 ## Contributing
 
-- [Add a theme](./docs/themes.md#adding-theme)
-- [Add a language grammar](./docs/languages.md#adding-grammar)
+See the [Contributing Guide](.github/CONTRIBUTING.md).
 
 ## Credits