Run `update_version.py` script if version is 'UNKNOWN'.
Run `update_version.py` script if version is 'UNKNOWN'.

Fixes #60

Signed-off-by: Tim 'mithro' Ansell <b1c1d8736f20db3fb6c1c66bb1455ed43909f0d8@mith.ro>

SymbiFlow/fasm,SymbiFlow/fasm