Add build:watch command

Author: Jaiheravi

package.json

@@ -25,7 +25,8 @@
     "node": ">=12.0.0"
   },
   "scripts": {
-    "build": "node ./cli/index.js compile src/concise.pcss dist/concise.css"
+    "build": "node ./cli/index.js compile src/concise.pcss dist/concise.css",
+    "build:watch": "node ./cli/index.js watch src/concise.pcss dist/concise.css"
   },
   "dependencies": {
     "autoprefixer": "^9.7.5",