Mention including cluster state archive in GitHub issues (#1892)
Mention including cluster state archive in GitHub issues (#1892)

* Mention including cluster state archive in GitHub issues

* Fix spelling by wrapping with backticks

* Indent with 4 spaces (MD007)

* Split into two paragraphs

* Use pre-formatted blocks

Followed instructions at
https://preliminary.istio.io/about/contribute/writing-a-new-topic/#embedding-preformatted-blocks

* Extract branch_name variable

istio/istio.io,linsun/istio.github.io,linsun/istio.github.io,linsun/istio.github.io,istio/istio.io,linsun/istio.github.io,istio/istio.io,istio/istio.io,geeknoid/istio.github.io,linsun/istio.github.io,istio/istio.io,istio/istio.io,istio/istio.io,geeknoid/istio.github.io,geeknoid/istio.github.io,geeknoid/istio.github.io,geeknoid/istio.github.io