message: docs: revise PUBLISHING.md S3 section
  Mention the production and snapshot S3 bucket
  Remove the note that `aws-s3.sh` doesn't run on Windows
  Don't document `./scripts/publish/aws-s3.sh`. Encourage maintainers to
  use `make publish-aws-s3` instead
  See:
diff: @@ -85,19 +85,10 @@ Publishing to S3
  - [AWS CLI][aws-cli]
  Make sure you have the [AWS CLI tool][aws-cli] installed and configured to
  -access resin.io's production downloads S3 bucket.
  +access resin.io's production or snapshot S3 bucket.
  -> The publishing script only runs on UNIX based operating systems for now. You
  -> can use something like [Cygwin][cygwin] to run it on Windows.
  -
  -Run the following command to publish a specific file:
  -
  -```sh
  -./scripts/publish/aws-s3.sh -f <file> -b <bucket> -v <version> -p <product name>
  -```
  -
  -Or run the following command to publish all files for the current combination
  -of _platform_ and _arch_ (building them if necessary) :
  +Run the following command to publish all files for the current combination of
  +_platform_ and _arch_ (building them if necessary):
  ```sh
  make publish-aws-s3 RELEASE_TYPE=<production|snapshot>
  @@ -124,7 +115,6 @@ Post messages to the [Etcher forum][resin-forum-etcher] and
  of Etcher, and including the relevant section of the Changelog.
  [aws-cli]: https://aws.amazon.com/cli
  -[cygwin]: https://cygwin.com
  [bintray]: https://bintray.com
  [etcher-cask-file]: https://github.com/caskroom/homebrew-cask/blob/master/Casks/etcher.rb
  [homebrew-cask]: https://github.com/caskroom/homebrew-cask
  