RPC: Implement ActionUpdate
The Write RPC supports a number of actions, one of which is
ActionUpdate. This is the trickiest action to implement because it requires more complex Merkle proofs than the other actions. (The other actions all operate at a sector level, whereas
ActionUpdate can operate on as little as 64 bytes.) It's completely doable, it just requires a bit more work than the others, and
ActionUpdate is also not necessary for the types of operations that we are prioritizing in the short term. It is, however, crucial to implementing a true multi-user Sia filesystem, which is not that far off. I suggest that we try to include this in v1.4.1, along with other host improvements.