Use commit message emoji

Inspired by [dannyfritz/commit-message-emoji](https://github.com/dannyfritz/commit-message-emoji)

See also [gitmoji](https://gitmoji.carloscuesta.me/).

| Commit type | Emoji |
|:---------------------------|:----------------------------------------------|
| Initial commit | :tada: `:tada:` |
| Version tag | :bookmark: `:bookmark:` |
| New feature | :sparkles: `:sparkles:` |
| Bugfix | :bug: `:bug:` |
| Metadata | :card_index: `:card_index:` |
| Documentation | :books: `:books:` |
| Documenting source code | :bulb: `:bulb:` |
| Performance | :racehorse: `:racehorse:` |
| Cosmetic | :lipstick: `:lipstick:` |
| Tests | :rotating_light: `:rotating_light:` |
| Adding a test | :white_check_mark: `:white_check_mark:` |
| General update | :zap: `:zap:` |
| Improve format/structure | :art: `:art:` |
| Refactor code | :hammer: `:hammer:` |
| Removing code/files | :fire: `:fire:` |
| Continuous Integration | :green_heart: `:green_heart:` |
| Security | :lock: `:lock:` |
| Upgrading dependencies | :arrow_up: `:arrow_up:` |
| Downgrading dependencies | :arrow_down: `:arrow_down:` |
| Lint | :shirt: `:shirt:` |
| Translation | :alien: `:alien:` |
| Text | :pencil: `:pencil:` |
| Critical hotfix | :ambulance: `:ambulance:` |
| Deploying stuff | :rocket: `:rocket:` |
| Fixing on MacOS | :apple: `:apple:` |
| Fixing on Linux | :penguin: `:penguin:` |
| Fixing on Windows | :checkered_flag: `:checkered_flag:` |
| Work in progress | :construction: `:construction:` |
| Adding CI build system | :construction_worker: `:construction_worker:` |
| Analytics or tracking code | :chart_with_upwards_trend: `:chart_with_upwards_trend:` |
| Removing a dependency | :heavy_minus_sign: `:heavy_minus_sign:` |
| Adding a dependency | :heavy_plus_sign: `:heavy_plus_sign:` |
| Docker | :whale: `:whale:` |
| Configuration files | :wrench: `:wrench:` |
| Package.json in JS | :package: `:package:` |
| Merging branches | :twisted_rightwards_arrows: `:twisted_rightwards_arrows:` |
| Bad code / need improv. | :hankey: `:hankey:` |
| Reverting changes | :rewind: `:rewind:` |
| Breaking changes | :boom: `:boom:` |
| Code review changes | :ok_hand: `:ok_hand:` |
| Accessibility | :wheelchair: `:wheelchair:` |
| Move/rename repository | :truck: `:truck:` |
| Other | [Be creative](http://www.emoji-cheat-sheet.com/) |

Review the commit-type and emoji table in the issue, along with the linked commit-message-emoji and gitmoji references. No repository file, test, or entry point is named, so first inspect the project’s contribution documentation to find where commit conventions belong. Done means the convention is recorded in an appropriate project document.

Written by the indexing model from the issue text.