Backport of Update K8s changelog to address cloud auto-join change in 1.0.0 into release/1.15.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #18293 to be assessed for backporting due to the inclusion of the label backport/1.15.

The below text is copied from the body of the original PR.

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Description

• Update the k8s 1.0.x changelog page to match Update changelog to address cloud auto-join change in 1.0.0 consul-k8s#2667. This calls out a cloud auto-join change in the externalServers.hosts field

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern

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Overview of commits

• 1584728

[github-team-consul-core-pr-approver]

Auto approved Consul Bot automated PR

[hc-github-team-consul-core]

🤔 This PR has changes in the website/ directory but does not have a type/docs-cherrypick label. If the changes are for the next version, this can be ignored. If they are updates to current docs, attach the label to auto cherrypick to the stable-website branch after merging.