Incorrect PHPDoc @param object types

## Bug report for Cloudinary PHP Transformation Builder SDK
Before proceeding, please update to the latest version and test if the issue persists

## Describe the bug in a sentence or two.
Incorrect PHPDoc tag for `Cloudinary\Transformation\TransformationResizeTrait::fill`. The `$gravity` argument is documented as taking an instance of `Cloudinary\Transformation\Gravity`, but in fact expects an instance of `Cloudinary\Transformation\GravityQualifier`. Presumably this is a bigger issue than just this one argument, but this is where PHPStan complains for me, so I thought I'd start somewhere.

## Issue Type (Can be multiple)
- [ ] Build - Can’t install or import the SDK
- [ ] Performance - Performance issues
- [ ] Behaviour - Functions aren’t working as expected (such as generate URL)
- [x] Documentation - Inconsistency between the docs and behaviour
- [ ] Other (Specify)