fix: add explicit dependency on chalk (#687)

@commitlint/load now explicitly depends on chalk, previously relying on it being resolved as a dependency of one it's other dependencies. this change allows tooling with strict dependency graph requirements (ex. Yarn PnP) to run commitlint seamlessly.

Author: meatwallace

@commitlint/load/package.json

@@ -71,6 +71,7 @@
     "@commitlint/execute-rule": "^8.0.0",
     "@commitlint/resolve-extends": "^8.0.0",
     "babel-runtime": "^6.23.0",
+    "chalk": "2.4.2",
     "cosmiconfig": "^5.2.0",
     "lodash": "4.17.11",
     "resolve-from": "^5.0.0"