(maint) Update GRM configuration

This commit makes a very small change to GRM configuration, to
add a space between the 2 emojis.  This doesn't cause problem
for GitHub, but it does in GitLab, so to keep things the same, let's
add the space.

GitReleaseManager.yaml

@@ -35,4 +35,4 @@ close:
     - [GitHub Release](https://github.com/{owner}/{repository}/releases/tag/{milestone})
     - [NuGet Package](https://www.nuget.org/packages/{repository}/{milestone})
 
-    Your **[GitReleaseManager](https://github.com/GitTools/GitReleaseManager)** bot :package::rocket:
+    Your **[GitReleaseManager](https://github.com/GitTools/GitReleaseManager)** bot :package: :rocket: