Update Sia version to v1.4.1.2-rc1

[jkawamoto]

Update Sia version to v1.4.1.2-rc1

[MeijeSibbel]

@everyone we have a surprise release candidate for all of you today - v1.4.1.2-rc1

The network has been struggling with some transaction propagation issues and we believe we've identified the cause and implemented a solution, need your help testing it though.

We only have siad today b/c it's late on a friday and eddie is on vacation, but the problem is pretty bad so we wanted to push this out anyway.

What we're looking out for is file contract, and ensuring that they are renewing successfully. Recently, not every file contract has been able to get confirmed on-chain, which of course threatens the data integrity. You can tell if your file contracts are on chain or not by looking at siac wallet transactions and seeing if your file contracts still say "unconfirmed" after a few blocks. If this fix seems to be working, we'll push out the full release. Thanks guys.

[jkawamoto]

We might also need to have a docker image for v1.4.1.1 so that we can fallback to the newest stable version.