Remove Guava dependency

[kubode]

Guava has some dependency issues as mentioned at here.

Guava has been introduced in Kakao 3.6.0 at fd7edfd.
Bumping up to 3.6.0 caused the dependency resolution issue on our project.
So we want to remove Guava from the dependency of Kakao.

[Unlimity]

Hi there. In a case like this, you can override transient dependency in your own project (you can look up how to do that here - https://stackoverflow.com/questions/30728533/gradle-override-transitive-dependency-by-version-classifier). But on the other hand, I don't see a reason why we imported it in the first place, as it seems from this PR that we use only 1 function of the whole library which can be replaced by Kotlin STD function. @Vacxe wdyt?

[Vacxe]

100% agree with replacement. If all checks passed I'll be happy to remove that dependency. Thanks for letting us know @kubode ! Cheers.

[Vacxe]

Released 3.6.2