Support Symfony 5

[GrahamCampbell]

No description provided.

[crynobone]

This now cause a regression bug when tested with Symfony 5.

- Installing symfony/options-resolver (dev-master 4c6fc48): Downloading (100%)

1) Katsana\Insurance\Tests\Passport\ClientCredentialsGrantTest::it_cant_attempt_to_authenticate_without_client_id_and_secret
Failed asserting that exception of type "TypeError" matches expected exception "InvalidArgumentException". Message was: "Argument 1 passed to Symfony\Component\OptionsResolver\OptionsResolver::setAllowedValues() must be of the type string, integer given, called in /home/travis/build/katsana/insurance-sdk-php/vendor/php-http/curl-client/src/Client.php on line 98" at

[dbu]

hmm... the curl constants indeed seem to be integer, and OptionsResolver is now declaring the type of the name as string. can you do a PR to cast those curl constants to string? and check whether passing curl options with integer keys still works in the resolver?