Fix deprecations with symfony 4.2 #289
Description
| Q | A |
|---|---|
| Bug? | not yet |
| New Feature? | no |
| Version | master |
Now that symfony 4.2 is released, the ci fails because tests, while being green, trigger a couple of deprecation notices: https://travis-ci.org/php-http/HttplugBundle/jobs/462460147
We should adjust those things, ideally while staying backwards compatible with all supported versions.