fix: copy typings to build directory

Author: aminya

package.json

@@ -16,9 +16,10 @@
     "test.format": "prettier . --check",
     "lint": "eslint . --fix --ext .ts",
     "test.lint": "eslint . --ext .ts",
-    "clean": "rimraf build",
-    "compile": "tsc",
-    "watch": "tsc -watch",
+    "clean": "shx rm -rf build && mkdirp build",
+    "copy.typings": "shx cp -r ./typings ./build",
+    "compile": "npm run copy.typings && tsc",
+    "watch": "npm run compile -- --watch",
     "prepare": "npm run clean && npm run compile",
     "test": "npm run compile && atom --test build/test"
   },
@@ -43,7 +44,7 @@
     "eslint": "^7.18.0",
     "mocha": "^8.2.1",
     "mocha-appveyor-reporter": "^0.4.2",
-    "rimraf": "^3.0.2",
+    "shx": "^0.3.3",
     "sinon": "^9.2.4",
     "typescript": "~4.1.3"
   }