Updating the Anker deployment

[ruuda]

Problem

Version 1.3.0 of the Anker program has been deployed at BNVB8pd4coHpY7MVcrtiHLCLst7fyDGzMtPmfJqFAhwj. This version contains a (non-exploitable) bug fixed by #566, that prevents sending proceeds to Terra. Currently, all maintainer bots are failing when they try to submit the SendRewards transaction (in simulation already, so the transaction never makes it to the chain).

Paths forward

We have two options:

1. Update the program. This requires uploading to a buffer account and then getting the multisig to approve the update.
2. Modify the maintainer to no longer try to call SendRewards. (And if it stops calling SendRewards, we might as well stop calling SellRewards.)

Normally we would go for option 1, but given the events of last week and the uncertainty around Anchor, it may not be worth the trouble, and we could also go for option 2.

CC @kkonevets