Update to angular 13. Maintain project

[Akkora]

Hi @georgipeltekov,

I did a maintenance of the demo for ngx-file-drop.

Added

• Link to GitHub

Maintenance

• Update to angular 13
• Update to ngx-file-drop 13
• Replace ng-bootstrap with plain bootstrap, as just css functionality is used
• Remove ng2-table (because it has no support for angular 13 and there is a table in bootstrap available)

Removed

• Pagination functionality (because it was part of ng2-table and I saw no benefit in rebuilding it)

Please check if its working like before. I have no experience with GitHub Pages. Locally it was working fine.