Code formatting should be run on CHANGELOG.md during release

[josephperrott]

During the release process, when the new Changelog entry is generated and added to the CHANGELOG.md file, we should leverage the formatFiles function from ng-dev/format/format to format the newly modified CHANGELOG.md file.

This notably presents as a failure on CI for CLI as markdown files are formatted using prettier.

[josephperrott]

Closed by #204

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