add comment for repo dispatch token

Author: birkenfeld

.github/workflows/trigger_website.yml

@@ -10,6 +10,9 @@ jobs:
       - name: Repository Dispatch
         uses: peter-evans/repository-dispatch@v3
         with:
+          # Personal access token in this repo's secrets, must be
+          # renewed every year (use a token from any developer with
+          # sufficient access)
           token: ${{ secrets.DISPATCHTOKEN }}
           repository: sampleenvironment/secop-site
           event-type: spec-update