Possible invalid datetime in FormatTest::getValidFormats

[matason]

Hi, I see that your working towards supporting draft-06, so I thought I'd try to help.

The first test failure I had was:

1) JsonSchema\Tests\Constraints\FormatTest::testValidFormat with data set #10 ('2000-05-01T12:12:12+0100', 'date-time')
Failed asserting that an array is empty.

I tracked this down to:

        yield ['2000-05-01T12:12:12+0100', 'date-time'];

in the getValidFormats method, which appears to be an invalid format for RFC3339.

I've opened a pull request to remove that line, please do close this issue (and I'll close the pull request), if I am wrong.

Best!

[github-actions]

🚀 @matason, thanks for your contribution! Every idea, bug report, and discussion helps make this project better. Your input is invaluable, and we appreciate the time you took to share it. A maintainer will review it soon—stay awesome! 💡✨

[DannyvdSluijs]

Thanks for the contribution. I'm still enjoying some summer holidays at the moment. So I expect it will take some longer time to review this.