chore: enforce commit message convention

Install commitizan so commit messages can be assembled interactively and with compliance to semantic
release conventions.

Author: gruhn

package.json

@@ -36,7 +36,8 @@
   "homepage": "https://github.com/gruhn/vue-qrcode-reader#readme",
   "husky": {
     "hooks": {
-      "pre-commit": "lint-staged"
+      "pre-commit": "lint-staged",
+      "prepare-commit-msg": "exec < /dev/tty && git cz --hook"
     }
   },
   "lint-staged": {
@@ -53,9 +54,11 @@
     "babel-plugin-transform-runtime": "^6.23.0",
     "babel-preset-es2015": "^6.14.0",
     "babel-preset-stage-0": "^6.16.0",
+    "commitizen": "^3.1.1",
     "cross-env": "^3.1.3",
     "cross-spawn": "^5.0.1",
     "css-loader": "^0.26.1",
+    "cz-conventional-changelog": "^2.1.0",
     "eslint": "^3.12.1",
     "eslint-config-prettier": "^4.1.0",
     "eslint-config-standard": "^6.2.1",
@@ -79,5 +82,10 @@
     "babel-runtime": "^6.26.0",
     "jsqr": "^1.2.0",
     "webrtc-adapter": "^6.2.1"
+  },
+  "config": {
+    "commitizen": {
+      "path": "./node_modules/cz-conventional-changelog"
+    }
   }
 }