message: docs: update release docs to reflect new tooling
  Release tooling was updated in to use dev-infra's unified system. The actual documentation was mostly copied from the existing [Angular CLI release docs](https://github.com/angular/angular-cli/blob/e0a1a94e79a3b0a5ec03bb41c70e8f8674557c10/docs/process/release.md), with the key difference being that releases and published as necessary rather than every week.
diff: -# Release Steps
  +# Release
  -- Login as `angular` npm account
  -- Update Angular deps in `package.json`, `tools/defaults.bzl` and run `yarn install` to update the yarn.lock file - [Example Commit](https://github.com/angular/universal/commit/bf252680e41ff41d57db6172cb0532aea646b32c)
  -- Update the version in `package.json` - [Example Commit](https://github.com/angular/universal/commit/fccca4b49f198fb9b6a52877db58909ebb419369)
  -- Create a release commit
  +Releasing is performed using Angular's unified release tooling. Releases are
  +done as needed when meaningful changes have landed in Universal.
  -```sh
  -git commit -a -m "release: v9.0.0-next.13" # (Update to version just put in package.json)
  -```
  -
  -- Create a tag
  -
  -```sh
  -git tag v9.0.0-next.13
  -```
  -
  -- Push commit and tag
  +To perform a release run the following and navigate the prompts:
  ```sh
  -git push upstream && git push upstream --tags
  +yarn ng-dev release publish
  ```
  -
  -- Wait for CI to be green at https://github.com/angular/universal/commits/${branch}.
  -- Publish
  -
  -```sh
  -# For release with 'next' tag
  -./publish.sh next
  -```
  -
  -```sh
  -# For release with 'latest' tag
  -./publish.sh latest
  -```
  -
  -# Release Changelog
  -
  -Release changelog needs to be included in two places, the GitHub release and in
  -the
  -[`CHANGELOG.md`](https://github.com/angular/universal/blob/master/CHANGELOG.md)
  -file. These use different formats, so start with GitHub by running:
  -
  -```sh
  -yarn -s ng-dev release notes --type=github-release --from=<The git tag or ref to start the changelog entry from>
  -```
  -
  -- Go to the [`Releases` tab](https://github.com/angular/universal/releases) in
  - the repository.
  -- Click on the newly created tag.
  -- Copy paste the output of the above command into the contents of the release.
  -- Choose `This is a prerelase` checkbox for pre-release versions.
  -
  -After creating a GitHub release, update the
  -[`CHANGELOG.md`](https://github.com/angular/universal/blob/master/CHANGELOG.md)
  -file by prepending it with changelog-formatted release notes (note
  -`--type=changelog` which is _different_ from the GitHub release):
  -
  -```sh
  -cat <(yarn -s ng-dev release notes --type=changelog --from=<The git tag or ref to start the changelog entry from>) \
  - CHANGELOG.md > CHANGELOG.md
  -```
  -
  -Then make a PR with the update targeting `master`, get a team member to review
  -it, and merge when ready.
  