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

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

Author: sreenathnair

.github/workflows/docker.yml

@@ -4,6 +4,9 @@ on:
   push:
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   valid_tag:
     if: github.ref_type == 'tag'