docs(downloads): update source code download links to use closer mirror (#36174)

* docs(downloads): update source code download links to use closer mirror

* added archived releases

Author: liferoad

contributor-docs/release-guide.md

@@ -670,9 +670,9 @@ This pull request is against the `apache/beam` repo, on the `master` branch
 - Update `CHANGES.md` to update release date and remove template.
 - Update release version in `website/www/site/config.toml`.
 - Add new release in `website/www/site/content/en/get-started/downloads.md`.
+   - For the current release, use `closer.lua` script for download links (e.g., `https://www.apache.org/dyn/closer.lua/beam/{{< param release_latest >}}/apache-beam-{{< param release_latest >}}-source-release.zip`)
    - Download links will not work until the release is finalized.
-- Update links to prior releases to point to https://archive.apache.org (see
-  example PR).
+- Move the previous release to the "Archived releases" section and update its links to point to https://archive.apache.org (see example PR).
 - Create the Blog post:
 
 #### Blog post