Memory cache conflicts when using the maxImageSize option

[h6ah4i]

Hi! I found an issue related to the recently introduced maxImageSize option.

The current default cache key generation logic does not take care about the option, so memory cache maybe returns different size images.

I know we can add own custom Keyer implementation to handle the situation, but I think this one should be handled in the library itself.

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Repro:
https://github.com/h6ah4i/ComposeImageLoaderMemCacheConfliction

Expected	Actual (the right image is NOT scaled)