Set minimal permissions to Github Workflows (#3972)

.github/workflows/publish_documentation.yml

@@ -10,6 +10,9 @@ on:
       - docs/examples/**
   workflow_dispatch:
 
+permissions:
+  contents: read
+
 # we don't want to have concurrent jobs, and we don't want to cancel running jobs to avoid broken publications
 concurrency:
   group: documentation