Update README.md. Add privacy and security considerations.

SHA: 4c1c38b
Reason: push, by QueenieZqq

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: QueenieZqq

index.html

@@ -8,7 +8,7 @@
   <meta content="Bikeshed version 3f621ba99, updated Mon Jul 28 15:38:36 2025 -0700" name="generator">
   <link href="https://explainers-by-googlers.github.io/proofreader-api" rel="canonical">
   <link href="https://www.w3.org/2008/site/images/favicon.ico" rel="icon">
-  <meta content="788b66083890441413fafae55d8c1b22c35573f1" name="revision">
+  <meta content="4c1c38bcdc615bbd92b9192b1abca3f00f9add74" name="revision">
   <meta content="dark light" name="color-scheme">
   <link href="https://www.w3.org/StyleSheets/TR/2021/dark.css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css">
 <style>/* Boilerplate: style-autolinks */
@@ -417,7 +417,7 @@
 </p>
    <h1 class="p-name no-ref" id="title">Proofreader API</h1>
    <p id="w3c-state"><a href="https://www.w3.org/standards/types/#UD">Unofficial Proposal Draft</a>,
-    <time class="dt-updated" datetime="2025-08-27">27 August 2025</time></p>
+    <time class="dt-updated" datetime="2025-08-28">28 August 2025</time></p>
    <details open>
     <summary>More details about this document</summary>
     <div data-fill-with="spec-metadata">