s/member/graduated (#1347)

Signed-off-by: lucperkins <lucperkins@gmail.com>

content/index.html

@@ -96,7 +96,7 @@ layout: jumbotron
       <p>Prometheus is 100% open source and community-driven. All components are available under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache 2 License</a> on <a href="https://github.com/prometheus">GitHub</a>.</p>
       <iframe src="https://ghbtns.com/github-btn.html?user=prometheus&repo=prometheus&type=star&count=true&size=large" frameborder="0" scrolling="0" class="github-stars"></iframe>
       <br><br>
-      <p>We are a <a href="https://cncf.io/">Cloud Native Computing Foundation</a> member project.</p>
+      <p>We are a <a href="https://cncf.io/">Cloud Native Computing Foundation</a> graduated project.</p>
       <br>
       <a href="https://cncf.io/"><img src="assets/cncf_logo.png"></a>
     </div>