feat: Added Theme and migrate to emotion@10.x 🚀 (#286)

* chore: updated emotion dependency

* feat: introduced theme

* refactor: updated emotion styles

* fix: fixed emotion error

* fix: fixed tests

* chore: add missing types

Co-Authored-By: Thomas Klein <tmkn@users.noreply.github.com>

src/components/Repository/Repository.test.tsx

@@ -1,5 +1,6 @@
 import React from 'react';
-import { mount } from 'enzyme';
+
+import { mount } from '../../utils/test-enzyme';
 
 import Repository from './Repository';