Potential fix for code scanning alert no. 3: Workflow does not contain permissions

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>
Signed-off-by: Robert Baldyga <robert.baldyga@open-cas.com>

Author: robertbaldyga

.github/workflows/c-cpp.yml

@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [ "master" ]
 
+permissions:
+  contents: read
+
 jobs:
   build: