fix workflow

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: rempairamore

.github/workflows/smoketest.yml

@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [ main, master ]
 
+permissions:
+  contents: read
+
 env:
   SPARQL_ENDPOINT_INDEX: https://sparql.opencitations.net/index
   SPARQL_ENDPOINT_META: https://sparql.opencitations.net/meta