* Updated lock-file to fix https://github.com/npm/cli/issues/4859.
* Updated integration-tests to webpack 5 to fix
https://github.com/webpack/webpack/issues/14532.
* Added `mode` to webpack-integration-tests to avoid
the warning `The 'mode' option has not been set...`.
* Replaced outdated `grunt-bg-shell`-package to get rid of
coffee-script warnings
Fixes the following error when running integration-tests:
```
npm ERR! code ERESOLVE
npm ERR! ERESOLVE unable to resolve dependency tree
npm ERR!
npm ERR! While resolving: webpack-test@1.0.0
npm ERR! Found: handlebars@5.0.0-alpha.1
npm ERR! node_modules/handlebars
npm ERR! dev handlebars@"file:../../.." from the root project
npm ERR!
npm ERR! Could not resolve dependency:
npm ERR! peer handlebars@">= 1.3.0 < 5" from handlebars-loader@1.7.1
npm ERR! node_modules/handlebars-loader
npm ERR! dev handlebars-loader@"^1.7.1" from the root project
npm ERR!
```
Jakob Linskeseder