Update production.rb template to provide example to exclude healthcheck from force_ssl redirect

[bensheldon]

Motivation / Background

This PR updates the production.rb template to provide an example for excluding the healthcheck from force_ssl redirect.

Instructions for disabling specific endpoints from http-to-https redirects live in the SSL middleware:

rails/actionpack/lib/action_dispatch/middleware/ssl.rb

Line 20 in fc4407e

# config.ssl_options = { redirect: { exclude: -> request { /healthcheck/.match?(request.path) } } }

The change follows the path-matching pattern already present for ignoring the healthcheck endpoint for config.host_authorization:

rails/railties/lib/rails/generators/rails/app/templates/config/environments/production.rb.tt

Line 110 in fc4407e

# config.host_authorization = { exclude: ->(request) { request.path == "/up" } }

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Unrelated changes should be opened in separate PRs.
• Commit message has a detailed description of what changed and why. If this PR fixes a related issue include it in the commit message. Ex: [Fix #issue-number]
• X Tests are added or updated if you fix a bug or add a feature.
• X CHANGELOG files are updated for the changed libraries if there is a behavior change or additional feature. Minor bug fixes and documentation changes should not be included.