Update action-markdownlint.yml

Author: Raj-StepSecurity

.github/workflows/action-markdownlint.yml

@@ -5,7 +5,8 @@ on:
     branches: [ main ]
   push:
     branches: [ main ]
-
+permissions:
+  contents: write
 jobs:
   call-markdown-lint:
     uses: step-security/workflow-playground/.github/workflows/action-markdown-lint.yml@main