docs(misc/Version Support Status): mention LTS extension by 6 months due to COVID

Due to COVID-19 affecting teams migrating from AngularJS, the Long Term Support period has been
extended by 6 months (until the end of 2021). See announcement on Twitter:
https://twitter.com/angular/status/1287780634572857357

This commit updates the "Version Support Status" page to also mention the extension.

Partially addresses #17058.

docs/content/misc/version-support-status.ngdoc

@@ -7,7 +7,11 @@
 This page describes the support status of the significant versions of AngularJS.
 
 <div class="alert alert-info">
-  On July 1, 2018 AngularJS entered a 3 year Long Term Support period.
+  On July 1, 2018 AngularJS entered a 3 year Long Term Support period.<br />
+  <br />
+  _**UPDATE (2020-07-27):**_<br />
+  _Due to COVID-19 affecting teams migrating from AngularJS, we are extending the LTS by six months
+  (until December 31, 2021)._
 </div>
 
 Any version branch not shown in the following table (e.g. 1.7.x) is no longer being developed.
@@ -42,6 +46,8 @@ We now focus exclusively on providing fixes to bugs that satisfy at least one of
 
 AngularJS 1.2.x will get a new version if and only if a new severe security issue is discovered.
 
+
+
 ### Blog Post
 
 You can read more about these plans in our [blog post announcement](https://blog.angular.io/stable-angularjs-and-long-term-support-7e077635ee9c).