Add permissions to fuzz workflow

Co-authored-by: dbanty <43723790+dbanty@users.noreply.github.com>

Author: Copilot

.github/workflows/fuzz.yml

@@ -1,5 +1,8 @@
 name: Fuzz code generation
 
+permissions:
+  contents: read
+
 on:
   push:
     branches: [ "main" ]