Add eval usage description

Author: aiqlcom

src/renderer/index.html

@@ -4,6 +4,7 @@
     <meta charset="utf-8" />
     <!-- default-src 'self'; should not be added due to fetch -->
     <!-- img-src 'self' data: -->
+    <!-- Enabling unsafe-eval due to ECharts Rendering: https://github.com/imzbf/md-editor-v3/blob/e1796bdba97b6fdc3b11dfc6f10897173b83d415/packages/MdEditor/layouts/Content/composition/useEcharts.ts#L100  -->
     <meta
       http-equiv="Content-Security-Policy"
       content="script-src 'self' 'unsafe-eval'; style-src 'self' 'unsafe-inline';"