Replace `coveralls` badge in readme with `codeclimate` badge

[wochinge]

Rasa Open Source version

main

Rasa SDK version

No response

Rasa X version

No response

Python version

Other

What operating system are you using?

OSX

What happened?

Replace coveralls badge in readme with codeclimate badge. Currently an old coverage report is shown.

Command / Request

No response

Relevant log output

No response

[thiagohdaqw]

Hi there This is still needed? I submited a PR for this https://github.com/RasaHQ/rasa/pull/11334