release: 4.7.1 (#5607)

* chore(release): bump version to 4.7.1

* docs: update MAINTAINING

* chore: update release_template

* chore: update CHANGELOG

* chore: bump helm chart version

* Update ci/helm-chart/Chart.yaml

Co-authored-by: Asher <ash@coder.com>

* fixup!: changelog

Co-authored-by: Asher <ash@coder.com>