Backport of Update changelog to include 1.6.0 into release/1.6.x

[hc-github-team-consul-core]

Backport

This PR is auto-generated from #4392 to be assessed for backporting due to the inclusion of the label backport/1.6.x.

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

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Changes proposed in this PR

• Port over changelog entry for 1.6.0

How I've tested this PR

👀

How I expect reviewers to test this PR

👀

Checklist

• Tests added
• CHANGELOG entry added

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Overview of commits

• 38e4b36

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