fix(kibisis): replace global object with window

[kieranroneill]

Description

Please explain the changes you made here

global was used to access the Web Crypto API to generate a UUID, but this only works in a Node.js environment and therefore throws a TypeError when run in a browser environment.

This fix changes the global reference to window to correctly reference the Web Crypto API in a browser environment.

Checklist

Please, make sure to comply with the checklist below before expecting review

• Code compiles correctly
• Created tests which fail without the change (if possible)
• All tests passing
• Extended the README / documentation, if necessary