Update old blog article about SIG Usability to mention dissolution (#42390)

* Update 2021-07-15-SIG-Usability-Spotlight.md

* Update content/en/blog/_posts/2021-07-15-SIG-Usability-Spotlight.md

Co-authored-by: Nitish Kumar <justnitish06@gmail.com>

* Update content/en/blog/_posts/2021-07-15-SIG-Usability-Spotlight.md

Co-authored-by: Nitish Kumar <justnitish06@gmail.com>

* Update content/en/blog/_posts/2021-07-15-SIG-Usability-Spotlight.md

Co-authored-by: Dipesh Rawat <rawat.dipesh@gmail.com>

* Update content/en/blog/_posts/2021-07-15-SIG-Usability-Spotlight.md

Co-authored-by: Tim Bannister <tim@scalefactory.com>

* Update content/en/blog/_posts/2021-07-15-SIG-Usability-Spotlight.md

Co-authored-by: Tim Bannister <tim@scalefactory.com>

* Update content/en/blog/_posts/2021-07-15-SIG-Usability-Spotlight.md

Co-authored-by: Tim Bannister <tim@scalefactory.com>

---------

Co-authored-by: Nitish Kumar <justnitish06@gmail.com>
Co-authored-by: Dipesh Rawat <rawat.dipesh@gmail.com>
Co-authored-by: Tim Bannister <tim@scalefactory.com>

content/en/blog/_posts/2021-07-15-SIG-Usability-Spotlight.md

@@ -5,7 +5,18 @@ date: 2021-07-15
 slug: sig-usability-spotlight-2021
 ---
 
-**Author:** Kunal Kushwaha, Civo
+**Author:** Kunal Kushwaha (Civo)
+
+{{< note >}}
+SIG Usability, which is featured in this Spotlight blog, has been deprecated and is no longer active.
+As a result, the links and information provided in this blog post may no longer be valid or relevant.
+Should there be renewed interest and increased participation in the future, the SIG may be revived.
+However, as of August 2023 the SIG is inactive per the Kubernetes community policy.
+The Kubernetes project encourages you to explore other
+[SIGs](https://github.com/kubernetes/community/blob/master/sig-list.md#special-interest-groups)
+and resources available on the Kubernetes website to stay up-to-date with the latest developments
+and enhancements in Kubernetes.
+{{< /note >}}
 
 ## Introduction