Fix PHP 8.1 deprecation notices

[AdrienPoupa]

This fixes the deprecation notices reported in #425 by specifying the int return type for the count functions.

Initially I wanted to use the master branch but it is lacking the Predis driver that we use.

I figured this would be more inclusive than using #[\ReturnTypeWillChange] given we only need to bump to PHP7 or higher and not PHP8.

Since this removes support for PHP5 (about time I guess? :)) I would suggest to release this as 0.14.0.

[petaritekako]

Hi guys,
when this will be merged and created new release?
We are using this package in our project and we also have this deprecation notice.

[holtkamp]

@sagikazarmark any way the community can help with this?

[kibertoad]

@sagikazarmark ping? can you give any update on the status of the project?