Update Needed flutter_cache_manager not compatible with rxdart last version

> Because no versions of flutter_cache_manager match >3.3.2 <4.0.0 and flutter_cache_manager >=3.0.2 <3.3.2 depends on rxdart >=0.26.0 <0.28.0, flutter_cache_manager >=3.0.2 <3.3.2-∞ or >3.3.2 <4.0.0 requires rxdart >=0.26.0 <0.28.0.
> And because flutter_cache_manager 3.3.2 depends on rxdart ^0.27.7 and cached_network_image 3.3.1 depends on flutter_cache_manager ^3.3.1, cached_network_image 3.3.1 requires rxdart >=0.26.0 <0.28.0.
> So, because project depends on both cached_network_image 3.3.1 and rxdart 0.28.0, version solving failed.