refactor: add npm clean script

package.json

@@ -6,7 +6,8 @@
     "scripts": {
         "test": "jest",
         "lint": "eslint .",
-        "build": "tsc",
+        "clean": "rimraf ./dist",
+        "build": "npm run clean && tsc",
         "prepare": "npm run build"
     },
     "files": [
@@ -29,6 +30,7 @@
         "@typescript-eslint/parser": "^4.21.0",
         "eslint": "^7.23.0",
         "jest": "^26.6.3",
+        "rimraf": "^3.0.2",
         "ts-jest": "^26.5.4",
         "typescript": "^4.2.3"
     },