ci: scope htmlvalidator workflow token to contents: read

Set an explicit least-privilege permissions block so the workflow GITHUB_TOKEN is scoped to contents: read instead of inheriting the repository default.

Signed-off-by: Arpit Jain <arpitjain099@gmail.com>

Author: arpitjain099

.github/workflows/htmlvalidator.yml

@@ -5,6 +5,9 @@ on:
     paths:
       - '**.htm*'
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest