add RC version string
siac version
and siad version
will now include the rc version in their output, e.g.:
Sia Client
Version 1.3.5-rc1
Git Revision c9a2fa38b
Build Time Tue Oct 2 14:30:09 EDT 2018
Sia Daemon
Version 1.3.5-rc1
Git Revision 094a56bc0
Build Time Tue Oct 2 13:13:08 EDT 2018
We may also want to consider setting a default value. That way, if you build directly from master, it could print 1.3.5-master
or 1.3.5-rc0
or something.
Fixes #3203 (closed)