feat: php 8 support

[ndench]

Just copied the nexylan/slack#70 pull request.

[ndench]

Symfony changed it configuration exception messages when updating to 5.0, so I had to modify a test. I dropped PHP 7.3 support because nexylan/slack#70 did the same.

The --prefer-lowest build is failing because it's installing PHPUnit 8.0 which seems to not be working with xdebug 3. I'm not sure how to fix this.

[soullivaneuh]

@ndench Thanks! Can you allow me edition on this PR so I can take a look and finish it?

[ndench]

No problem @soullivaneuh. I've invited you to my fork as a maintainer, feel free to make any changes necessary. I'm happy to help with anything you need as well.

[soullivaneuh]

@ndench Thanks, but by allowing edition, I meant simply this: https://docs.github.com/en/github/collaborating-with-issues-and-pull-requests/allowing-changes-to-a-pull-request-branch-created-from-a-fork

😉

[ndench]

Unfortunately allowing edits from maintainers appears to only work if the fork is created from a user account. However I created this fork from an organisation account so that checkbox is not available for me. See https://github.community/t/how-can-we-enable-allow-edits-from-maintainers-by-default/2847/6

I do not see the checkbox shown in the docs link:

Feel free to edit as a maintainer, or even create a separate branch and pull in my commits if you like.
I could also re-fork the repository if that's easier too?

[ndench]

@soullivaneuh I got the test passing. The --prefer-lowest option was installing a version of php-code-coverage which wasn't reading the xdebug mode properly. See this issue. It was also installing PHPUnit 8.0 which doesn't have the new expectExceptionMessageMatches function which was introduced it 8.4.

We can solve these by:

• Specifying XDEBUG_MODE=coverage as mentioned in the linked issue above
• Requiring PHPUnit minimum 8.4

[soullivaneuh]

Hello,

Thanks for giving some time on it! 👍

Looks goot to me.