Added copyright to license

[vkarai]

PR Checklist:

• I have run npm test locally and all tests are passing.
• I have added/updated tests for any new behavior.
  
• If this is a significant change, an issue has already been created where the problem / solution was discussed: [N/A, or add link to issue here]
  

PR Description

[wolfganggallo]

Thumbs up on this request. Since the Apache 2.0 license requires the preservation of the copyright notice at distribution, you are making it hard to impossible to use your library legally in Germany where copyright can not be waivered. I'm not a lawyer, this is just what they tell me ;-) Maybe this link helps: https://www.disclaimergenerator.net/copyright-notices/