v3.5.5

This supports IE11 again. (v3.5.3 and v3.5.4 have an issue.)
It also has various fixes and improvements in the persist middleware.

• #455 fix(persist): onRehydrateStorage argument not containing the final state
• #466 feat(persist): add a merge function option
• #462 fix: do not use generator to support IE11
• #468 fix(persist): incorrect deserialize return type
• #470 fix(persist): not hydrating when the stored item doesn't contain a version