Update SUPPORT.md (#3074)

* Update SUPPORT.md

Changed to the active discussions place

* Change link name

Author: ymesika

SUPPORT.md

@@ -3,5 +3,5 @@
 Here are some resources to help you understand and use Istio:
 
 - For in-depth information about how to use Istio, visit [istio.io](https://istio.io)
-- To ask questions and get assistance from our community, visit [discuss.istio.io](https://discuss.istio.io)
+- To ask questions and get assistance from our community, visit [GitHub Discussions](https://github.com/istio/istio/discussions)
 - To learn how to participate in our overall community, visit [our community page](https://istio.io/about/community)