🍱 Add CHANGELOG.md (kivy#2232)

* 🍱 Add CHANGELOG.md

This changelog was automatically generated by [github_changelog_generator](https://github.com/github-changelog-generator/github-changelog-generator)

* 🎨 Add/remove backslashes

To:
  - make sure that emoji are correctly detected
  - prevent emoji detection when a non-emoji text is encapsulated between **:**
  - render as expected words that are between  **\`**