fix: used diff. node-toggl-api package fixing upcoming API change

[natterstefan]

Issue

What I did

• use a different package, that uses the updated API domain of toggl. Because they change it at the end of June 2021.
  

What it adds, solves and/or improves

• added new intermittent package, that will (should) be replaced in the future to a new and maintained npm package

How to test

At the moment travis is failing, because of #27, that is why you have to test this change manually.

• build the package with npx vsce package
• install the generated *.vsix extension manually
• test the app