Fix faulty return type hint.

[martinssipenko]

Summary

Fixes faulty return type hint which leads to PHPStan reporting following error when I implement UserProfileServiceInterface.

Return type (array<int, mixed>|null) of method App\UserProfileService::lookup()
should be compatible with return type (Optimizely\UserProfile\userProfile) of
method Optimizely\UserProfile\UserProfileServiceInterface::lookup()

[coveralls]

Coverage decreased (-0.3%) to 97.149% when pulling 5f7c64d on martinssipenko:patch-1 into fa9a3bf on optimizely:master.

[martinssipenko]

@msohailhussain I believe CI checks are unrelated to my changes, could you please advise on how to move this foreward?

[rafinutshaw-optimizely]

Hi @martinssipenko ,
We've just published a patch version of the Optimizely PHP SDK to https://packagist.org/packages/optimizely/optimizely-sdk

Please update your PHP application, and you should be good to go.