Update color of note on download/debian page

Author: flashcode

weechat/templates/download/debian.html

@@ -35,7 +35,7 @@
 </div>
 {% endif %}
 
-<div class="alert alert-primary">
+<div class="alert alert-secondary">
   {% trans "<strong>Important:</strong> these packages are not Debian official packages; please <strong>read instructions</strong> below before using these repositories." %}
 </div>