Add explicit permissions to Tcl lint workflow

Added explicit 'contents: read' permission to the workflow to follow
security best practices and address CodeQL security alert.

Co-authored-by: nikosavola <7860886+nikosavola@users.noreply.github.com>

.github/workflows/tcl-lint.yaml

@@ -6,6 +6,8 @@ jobs:
   tcl-lint:
     runs-on: ubuntu-latest
     name: Tcl Code Quality
+    permissions:
+      contents: read
 
     steps:
       - name: Checkout source