Add support for V6

This PR adds support for WDIO V6 and has a temporary fix for #23.

Currently custom metadata, see https://github.com/wswebcreation/wdio-cucumberjs-json-reporter#metadata, is not supported in V6 due to a change between V5 and V6. I'm currently working on it

Contains:

• Merge pull request #24 from wswebcreation/v6 5c7fb2f
• feat: add support for V6 ea81702
• test: fix CI 36c7f6d

v1.1.3...v1.2.0