Update dependency `del` to v8

`del` is updated to get rid of the `rimraf` and `glob` deprecation warnings closes #757 <!-- Thanks for submitting a pull request 🙌 **Note:** Please don't create a pull request which has significant changes (i.e. adds new functionality or modifies existing one in a non-trivial way) without creating an issue first. Try to limit the scope of your pull request and provide a general description of the changes. If this fixes an open issue, link to it in the following way: `Fixes #321`. New features and bug fixes should come with tests. -->