ci: run markdownlint ci job only for README.md

Author: j-g00da

.github/workflows/ci.yml

@@ -32,7 +32,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: DavidAnson/markdownlint-cli2-action@v19
         with:
-          globs: '**/*.md'
+          globs: 'README.md'
 
   fmt:
     name: Run fmt