Update version numbering from 1.6 to 2.0.
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index c506a05..55db0e1 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -716,7 +716,7 @@
times are set to the current time. Otherwise, \var{times} must be a
2-tuple of numbers, of the form \code{(\var{atime}, \var{mtime})}
which is used to set the access and modified times, respectively.
-\versionchanged[added support for \code{None} for \var{times}]{1.6}
+\versionchanged[added support for \code{None} for \var{times}]{2.0}
Availability: Macintosh, \UNIX{}, Windows.
\end{funcdesc}