Update .github/config.yml

Author: reshamas

.github/config.yml

@@ -19,7 +19,7 @@ newPRWelcomeComment: >
 
 # Comment to be posted to on pull requests merged by a first time user
 firstPRMergeComment: >
-  ![Congratulations Banner](https://raw.githubusercontent.com/pymc-devs/brand/main/welcome-bot/BannerCongratulations.jpg)]
+  ![Congratulations Banner](https://raw.githubusercontent.com/pymc-devs/brand/main/welcome-bot/BannerCongratulations.jpg)
 
   Congrats on merging your first pull request! :tada:
   We here at _PyMC_ are proud of you! :sparkling_heart: