[Unison-hackers] New beta release coming -- 2.50 or 2.51

[Andrew Schulman]

> Dear unison hackers,
> 
> We’re getting ready to publish a new beta release of Unison, and we have a question about what major version number to give it.
> 
> The version number got bumped to 2.51 for a while in the master branch of the git repo, but later I realized that there was no need for this, since the set of preferences hasn’t changed.  Yesterday, I changed it back to 2.50, but this apparently confused at least one person who had already installed 2.51.  
> 
> If a lot of people have already installed 2.51 then we should just put it back to 2.51.  This is what I will do (later today) by default, since I have no way of knowing how many people this is.

Cygwin has already released a unison2.51 package. We could remove it, but
it'd be easier to have a new release of unison 2.51.x.

Thanks,
Andrew