Fix rewinddir() return type

[steevanb]

phpstan/phpstan#3232

[ondrejmirtes]

Thank you!

[phil-davis]

Note: these sort of changes are not "strictly backwards-compatible".
owncloud/core#37335 - CI broke because it was "expecting this error and ignoring it" but now the bug has been fixed and so the error does not happen and phpstan complains.

I don't know what you should do about these sort of fixes - actually the fix is "a good thing" (tm) - but suddenly people's CI breaks.

[ondrejmirtes]

@phil-davis Yeah, my stance is that most people are glad that PHPStan finds new bugs in their code.

If you want to minimize chances your CI will break, you can:

1. Set reportUnmatchedIgnoredErrors to false to prevent the error you're talking about.
2. Require specific PHPStan version 0.12.22 instead of a looser constraint like ^0.12.22 if you really want your build to stay green.

PHPStan is honoring backwards compatibility in the sense that your configuration file will not break in minor versions (0.12.x - when x increases), and also that the extensions API remains the same in minor versions.