`SebastianBergmann\CodeCoverage\Filter::includeDirectory` is deprecated but still mentioned in the README.md

[lyrixx]

ref: https://github.com/sebastianbergmann/php-code-coverage/blob/main/src/Filter.php#L31-L34
and: https://github.com/sebastianbergmann/php-code-coverage/blob/main/README.md?plain=1#L34