Added command to remove `typings` directory before its build

package.json

@@ -102,7 +102,7 @@
     "start": "yarn run watch",
     "webpack:prod": "webpack --config ./webpack/webpack.node.config.js --config ./webpack/webpack.browser.config.js --mode production",
     "build": "yarn run webpack:prod && yarn run eslint && yarn test",
-    "build:typings": "tsc --project src/tsconfig.typings.json",
+    "build:typings": "rm -rf ./typings && tsc --project src/tsconfig.typings.json",
     "watch": "webpack --config ./webpack/webpack.node.config.js --mode development --watch",
     "test:dev": "ts-node --type-check test/dev/dev.ts",
     "test:devCompilePerformance": "ts-node test/dev/dev-compile-performance.ts",