Potential fix for code scanning alert no. 1: Workflow does not contain permissions

fixing github

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

Author: umpire274

.github/workflows/rust.yml

@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [ "master" ]
 
+permissions:
+  contents: read
+
 env:
   CARGO_TERM_COLOR: always