✨ feat(.github/holopin.yml): add holopin configuration file to manage community contributions (#26808)

The new holopin.yml file will help manage community contributions by assigning stickers to contributors. This will make it easier to recognize and appreciate the efforts of our community contributors, fostering a more engaging and rewarding open-source environment.

Co-authored-by: Mattermost Build <build@mattermost.com>

.github/holopin.yml

@@ -0,0 +1,5 @@
+organization: mattermost # org name on holopin
+defaultSticker: clul38u2n156490gl8ti3srnek # sticker ID for "Mattermost QA Community Contributors", can be changed in the future
+stickers:
+  - id: clul38u2n156490gl8ti3srnek # sticker id
+    alias: Mattermost QA Community Contributors # shorthand-string