Labs: update your packages at the beginning

This corresponds to issues that some people faced installing
some packages, on a distro they had for quite some time.

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>

labs/setup/setup.tex

@@ -18,6 +18,16 @@ \section{Install lab data}
 the various practical labs. It will also be used as working space,
 in particular to keep generated files separate when needed.
 
+\section{Update your distribution}
+
+To avoid any issue installing packages during the practical labs,
+you should apply the latest updates to the packages in your distro:
+
+\begin{bashinput}
+$ sudo apt update
+$ sudo apt dist-upgrade
+\end{bashinput}
+
 You are now ready to start the real practical labs!
 
 \section{Install extra packages}