Remove unnecessary ext argument

Author: wojtekmaj

package.json

@@ -17,7 +17,7 @@
     "build-cjs": "tsc --project tsconfig.build.json --outDir dist/cjs --module commonjs",
     "clean": "rimraf dist",
     "jest": "jest",
-    "lint": "eslint src --ext .js,.ts",
+    "lint": "eslint src",
     "postinstall": "husky install",
     "prepack": "yarn clean && yarn build",
     "prettier": "prettier --check . --cache",