docs: ✏️ Add commitType to config docs

Add the commitType key and description to the configuration table

✅ Closes: #710

docs/bot/configuration.md

@@ -22,6 +22,7 @@ These are the keys you can specify:
 | `imageSize` | Size (in px) of the user's avatar. | Default: `100` |
 | `commit` | Auto-commit badge when adding contributors. | Default: `false` |
 | `commitConvention` | Commit convention ([`angular`](https://github.com/angular/angular/blob/master/CONTRIBUTING.md#-commit-message-guidelines), [`atom`](https://github.com/atom/atom/blob/master/CONTRIBUTING.md#git-commit-messages), [`ember`](https://guides.emberjs.com/v1.10.0/contributing/#toc_commits), [`eslint`](https://eslint.org/docs/1.0.0/developer-guide/contributing#step-2-make-your-changes), [`jshint`](https://jshint.com/contribute/), [`gitmoji`](https://gitmoji.carloscuesta.me/), or `none`). | Default: `angular` |
+| `commitType` | Set the `tag` for the commit in your chosen `commitConvention` (read more at [`commit-conv`](https://github.com/Berkmann18/commit-conv#parameters)) | Default: `docs` |
 | `contributorsPerLine` | Maximum number of columns for the contributors table. | Default: `7` |
 | `contributorsSortAlphabetically` | `true`: Sort alphabetically. `false`: Display in order of addition. | Default: `false` |
 | `badgeTemplate` | Define your own lodash template to generate the badge. | |