Add note about brand icons to issue template (#287)

.github/ISSUE_TEMPLATE/icon_request.md

@@ -6,10 +6,13 @@ labels: "icon request"
 
 <!--
 Before creating an icon request, please search to see if someone has requested the icon already. If there is an open request, please add a 👍.
+A note about brand logos and related material : We follow the decision from Feather Icons (https://github.com/feathericons/feather/issues/763) to deprecate icons relating to brands.
+You will find some in the set, but we won't add any new ones. https://simpleicons.org has 24x24 SVG icons for this purpose.
+
 -->
 
 ## Icon Request
 
 * Icon name:
 * Use case:
-* Screenshots of similar icons:
+* _Screenshots_ of similar icons: