build script should clean build dir

Author: seveibar

package.json

@@ -8,7 +8,7 @@
     "use-event-callback": "^0.1.0"
   },
   "scripts": {
-    "build": "npm run build:babel && cp ./package.json ./dist/package.json",
+    "build": "rimraf dist && npm run build:babel && cp ./package.json ./dist/package.json",
     "build:babel": "NODE_ENV=production babel ./src --out-dir=./dist",
     "release": "npm run build && cd dist && npm publish",
     "storybook": "start-storybook -p 9050 -s public",
@@ -51,6 +51,7 @@
     "react-scripts": "2.1.3",
     "react-select": "^3.0.8",
     "react-syntax-highlighter": "^10.3.0",
+    "rimraf": "^3.0.2",
     "spelling": "^2.0.1"
   }
 }

yarn.lock

@@ -11860,6 +11860,13 @@ rimraf@^2.2.8, rimraf@^2.5.4, rimraf@^2.6.1, rimraf@^2.6.2, rimraf@^2.6.3, rimra
   dependencies:
     glob "^7.1.3"
 
+rimraf@^3.0.2:
+  version "3.0.2"
+  resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-3.0.2.tgz#f1a5402ba6220ad52cc1282bac1ae3aa49fd061a"
+  integrity sha512-JZkJMZkAGFFPP2YqXZXPbMlMBgsxzE8ILs4lMIX/2o0L9UBw9O/Y3o6wFw/i9YLapcUJWwqbi3kdxIPdC62TIA==
+  dependencies:
+    glob "^7.1.3"
+
 rimraf@~2.6.2:
   version "2.6.3"
   resolved "https://registry.yarnpkg.com/rimraf/-/rimraf-2.6.3.tgz#b2d104fe0d8fb27cf9e0a1cda8262dd3833c6cab"