build(deps-dev): update cz-conventional-changelog requirement

Updates the requirements on [cz-conventional-changelog](https://github.com/commitizen/cz-conventional-changelog) to permit the latest version.
- [Release notes](https://github.com/commitizen/cz-conventional-changelog/releases)
- [Commits](commitizen/cz-conventional-changelog@v1.2.0...v2.1.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

package.json

@@ -44,7 +44,7 @@
     "chai-string": "1.5.0",
     "codecov": "3.5.0",
     "commitizen": "3.1.1",
-    "cz-conventional-changelog": "1.2.0",
+    "cz-conventional-changelog": "2.1.0",
     "eslint": "3.19.0",
     "eslint-config-kentcdodds": "11.1.0",
     "eslint-plugin-babel": "4.1.2",