Declare permissions for labeler-train workflow

Author: jeffhandley

.github/workflows/labeler-train.yml

@@ -45,6 +45,11 @@ on:
         required: true
         default: "staging"
 
+permissions:
+  issues: read
+  pull-requests: read
+  actions: write
+
 jobs:
   # Without specifying a pageSize of 1 for downloading pull requests, the requests time out
   # Directly invoking the individual workflows until https://github.com/dotnet/issue-labeler/issues/97 is addressed