[Infrastructure] Add a mention about ways to turn an issue into confidential

[Andrea Veri <averi src gnome org>]

commit 58f7d46f2e773c45fecf8a07e4d701d47b0274a6
Author: Andrea Veri <averi redhat com>
Date:   Tue Oct 29 17:19:09 2019 +0100

    Add a mention about ways to turn an issue into confidential

 .gitlab/issue_templates/default-template.md | 5 +++++
 1 file changed, 5 insertions(+)
---
diff --git a/.gitlab/issue_templates/default-template.md b/.gitlab/issue_templates/default-template.md
index da29732..4ab1f5c 100644
--- a/.gitlab/issue_templates/default-template.md
+++ b/.gitlab/issue_templates/default-template.md
@@ -24,6 +24,11 @@ Mailing lists, Planet, Mirrorbrain, Openshift, Build services)
 (Paste any relevant logs - please use code blocks (```) to format console output,
 logs, and code as it's very hard to read otherwise.)
 
+If you believe this issue should be marked as confidential due to the information
+it contains (IPs, your full name or other personal details), please un-comment the last
+line of this template.
+
 
 /label ~bug ~reproduced ~needs-investigation
 /cc @averi @barthalion
+#/confidential