Project: Add contributor list to all repositories

[stephanie-anderson]

Description

We want to show our gratitude towards contributors. One little thing we can start doing today is adding them to the README of our repositories. The Python SDK already did it:

## Thanks to all the people who contributed!

<a href="https://github.com/getsentry/sentry-python/graphs/contributors">
  <img src="https://contributors-img.web.app/image?repo=getsentry/sentry-python" />
</a>

Why should we be doing this?

Show some gratefulness.

Why now?

About time :D

### Repositories
- [x] sentry-python
- [x] sentry-ruby
- [x] sentry-elixir
- [x] sentry-php
- [ ] https://github.com/getsentry/sentry-javascript/pull/12632
- [ ] https://github.com/getsentry/sentry-electron/pull/929
- [ ] sentry-symfony
- [ ] sentry-laravel
- [ ] sentry-dotnet
- [ ] sentry-java
- [ ] sentry-cli
- [ ] sentry-go