yocto: slides: Add info about the versions and release scheme

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

slides/yocto-overview/yocto-overview.tex

@@ -92,14 +92,22 @@ \subsection{The Yocto Project overview}
 \subsection{The Poky reference system overview}
 
 \begin{frame}
-  \frametitle{Download the Poky reference system}
+  \frametitle{Getting the Poky reference system}
   \begin{itemize}
     \item All official projects part of the Yocto Project are
           available at \url{https://git.yoctoproject.org/cgit/}
     \item To download the Poky reference system: \\
           {\small
           \code{git clone -b dunfell git://git.yoctoproject.org/poky.git}
           }
+    \item Each release has a codename such as \code{dunfell} or \code{hardknott},
+	  corresponding to a release number.
+		  \begin{itemize}
+			  \item A summary can be found at \url{https://wiki.yoctoproject.org/wiki/Releases}
+		  \end{itemize}
+    \item A new version is released every 6 month, and maintained for 7 months
+    \item \textbf{LTS} versions are maintained for 2 years, and announced before their release.
+
   \end{itemize}
 \end{frame}