test(cli): migrates tests from ava to jest (#907)

* test(cli): migrates tests from ava to jest

* test: fix stdout -> stderr

* test(cli): update comments

* chore: change main to index.js and update types

Author: armano2

@commitlint/cli/package.json

@@ -14,18 +14,9 @@
     "build": "cross-env NODE_ENV=production babel src --out-dir lib --source-maps",
     "deps": "dep-check",
     "pkg": "pkg-check",
-    "start": "concurrently \"ava -c 4 --verbose --watch\" \"yarn run watch\"",
-    "test": "ava -c 4 --verbose",
+    "start": "yarn run watch",
     "watch": "babel src --out-dir lib --watch --source-maps"
   },
-  "ava": {
-    "files": [
-      "lib/**/*.test.js"
-    ],
-    "source": [
-      "lib/**/*.js"
-    ]
-  },
   "babel": {
     "presets": [
       "babel-preset-commitlint"
@@ -58,7 +49,6 @@
     "@babel/register": "^7.7.7",
     "@commitlint/test": "8.2.0",
     "@commitlint/utils": "^8.3.4",
-    "ava": "2.4.0",
     "babel-preset-commitlint": "^8.2.0",
     "concurrently": "3.6.1",
     "cross-env": "6.0.3",