docs/website: change wording about training provided by Bootlin

As suggested by Yann, let's avoid announcing the exact date of the
next course, as it gets outdated very often. Instead, use a more
generic wording and simply point to a Bootlin page that has all the
details.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

docs/website/docs.html

@@ -108,14 +108,13 @@
 	  </div>
 
 	  <div class="panel panel-default">
-	    <div class="panel-heading">Public training course</div>
+	    <div class="panel-heading">Public online training course</div>
 	    <div class="panel-body">
-	      The next online public training course on Buildroot
-	      organized
-	      by <a href="https://www.bootlin.com">Bootlin</a> will
-	      take place from May 31 to June 4, 2021, with Thomas Petazzoni as
-	      trainer. <a href="https://bootlin.com/training/buildroot/">Infos</a>
-	      and <a href="https://www.eventbrite.com/e/bootlin-embedded-linux-development-with-buildroot-training-seminar-tickets-145276318379">registration</a>.
+	      Regular online training courses, available to individual
+	      registration, are proposed by Bootlin, with Thomas
+	      Petazzoni as
+	      trainer. See <a href="https://bootlin.com/training/buildroot/">next
+	      dates and registration details</a>.
 	    </div>
 	  </div>
 	</div>