message: Add prerelease env var to publishing instructions
diff: @@ -1053,6 +1053,7 @@ Some integration tests rely on mocked server data (service:check for example). M
  - Can use major, minor, patch, prepatch, etc for the bump type. If not used, the command will prompt and ask for the bump type.
  - This command updates git tags locally and on GitHub
  3. Run npm run release:start-ci-publish locally
  + - IMPORTANT: If publishing a prerelease (like `alpha`/`beta`/`rc`), set the tag that NPM will use to publish with the `APOLLO_DIST_TAG` environment variable. By default, if this isn't set, NPM will publish the prerelease to the `latest` tag (which isn't what we'd want).
  - Pushes a `publish/XXXXXXXXXX` tag to GitHub to trigger circle CI build
  4. Circle will notify the appropriate Apollo team slack channel when ready to release
  - Slack channel member will confirm through the Apollo Deploy Bot
  