With PhpUnit 10 came the ability to use Php attributes rather than doc-block annotations for things like "data provider". PhpUnit 11 deprecates the use of annotations, and PhpUnit 12 will not not permit their use. Since PhpUnit 11 requires Php8.2+, we cannot adopt it as long as we support Php8.1, which will continue to be the case for some time. However, there is no penalty for early adoption.
Php-cs-fixer can use:
```
'php_unit_attributes' => ['keep_annotations' => false],
```
This allows us to run `composer fix` to automate all the needed changes. No manual changes were needed for any of the test members.
With this change, PhpUnit 9 can no longer be used with the test suite. File composer.json is updated to reflect that reality, and phpunit9.xml.dist, which has been supplied in case anyone needed to use PhpUnit 9, is no longer required, and is thus deleted. For now, PhpUnit 11 is not being added as a possibility.
No source code is changed in this PR.
Fix#912, opened in Feb. 2019, and closed as stale in Apr. 2019, and which I have re-opened to be closed properly by this PR. Another "better late than never". Original issue says that print options should not affect ShowGridlines, which seems true enough. Aside from that, the existing code isn't quite correct anyhow. Excel looks for 2 attributes, one of which must be explicitly set to true and the other of which must not be explicitly set to false, in order to determine whether PrintGridlines should be set. PhpSpreadsheet is changed to do the same. This could be treated as a BC break for the unusual situation described in the issue, but it seems more like a bug fix to me.
oleibman