Support SF6

[frenchcomp]

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	no
Deprecations?	no
Related tickets	fixes #60
Documentation	n/a
License	MIT

What's in this PR?

Update the composer.json file to use this library with project build on Symfony 6.0

Why?

This library requires symfony/options-resolver from 2.6 to 5.4

Checklist

• [x ] Updated CHANGELOG.md to describe BC breaks / deprecations | new feature | bugfix
• Documentation pull request created (if not simply a bugfix)

To Do

• If the PR is not complete but you want to discuss the approach, list what remains to be done here

[frenchcomp]

Hi,
Is this project still maintained? Your CI seems broken.
Thanks
Richard

[wmouwen]

Hi there.

We are wondering the same as @frenchcomp . The issue this PR resolves is slowly becoming a blocking issue.

Thanks.

[andrew-demb]

@joelwurtz @sagikazarmark @Nyholm @xabbuh
Hi. Could you help with proceeding with this PR, please?

[wmouwen]

Reminder for @joelwurtz and @Nyholm . This issue has become blocking for us. Could you help us with proceeding this PR?

[Nyholm]

The option resolver has not changed since 2.0. This is safe to merge.

Im hesitant to release this before we have proper CI again. See #63