Hey @ellenhelena!
At the moment there isn't support for dynamically setting font weight or text color in that way though there is an internal feature request for supporting more style options in the new table.
Based on your comment it sounds like you may be using the legacy table though, is that the case? If you are, there's a temporary workaround using custom css you might try for making selected rows bold:
#rt-table-yourTableId .selected{
font-weight: bold;
}

I'm not finding a workaround for changing the text color for edited rows though perhaps you meant something different by "updated"?
Let me know what you think!