slides/buildroot-support-contribution: use a working pastebin site

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

slides/buildroot-support-contribution/buildroot-support-contribution.tex

@@ -52,7 +52,7 @@ \section{Buildroot community: support and contribution}
     \item Include the Buildroot version, Buildroot \code{.config} that
       reproduces the issue, and last 100-200 lines of the build
       output in your report.
-    \item Use {\em pastebin} sites like \code{http://code.bulix.org}
+    \item Use {\em pastebin} sites like \code{https://paste.ack.tf/}
       when reporting issues over IRC.
     \end{itemize}
   \item The community will be much more likely to help you if you use