chore: copy .npmignore into dist folder to avoid publishing test folder

- related to issue opened in ng-packagr ng-packagr/ng-packagr#2459

Author: ghiscoding

package.json

@@ -21,7 +21,7 @@
     "postinstall": "ngcc",
     "prebuild": "npm-run-all delete:dist lint",
     "build": "npm run packagr",
-    "postbuild": "npm-run-all copy:i18n copy:lib",
+    "postbuild": "npm-run-all copy:i18n copy:npmignore",
     "build:with-e2e": "npm-run-all build cypress:ci",
     "build:gh-demo": "npm run build",
     "postbuild:gh-demo": "npm-run-all del-demo:dist copy-demo:dist",
@@ -39,7 +39,7 @@
     "jest:coverage": "npx jest --config test/jest.config.js --runInBand --coverage",
     "jest:snapshot": "npx jest --config test/jest.config.js --coverage -u",
     "copy:i18n": "cross-env copyfiles -f src/assets/i18n/*.json dist/i18n",
-    "copy:lib": "cross-env copyfiles --up 2 src/assets/lib/** dist",
+    "copy:npmignore": "cross-env copyfiles -f .npmignore dist",
     "packagr": "ng-packagr -p ng-package.json",
     "build:demo": "ng build --configuration=production --base-href=\"\"",
     "pack-lib": "npm pack ./dist",