Switch HTTP to HTTPS

[karlhorky]

Why:

• HTTPS protocol is more secure
• HTTP redirects to HTTPS anyway

See Heroku deploy preview here: https://docs-2941--patch-1.herokuapp.com/en/github/authenticating-to-github/removing-sensitive-data-from-a-repository#purging-a-file-from-your-repositorys-history

What's being changed:

Check off the following:

• I have reviewed my changes in staging. (look for the deploy-to-heroku link in your pull request, then click View deployment)
• For content changes, I have reviewed the localization checklist
• For content changes, I have reviewed the Content style guide for GitHub Docs.

[welcome]

Thanks for opening this pull request! A GitHub docs team member should be by to give feedback soon. In the meantime, please check out the contributing guidelines.

[janiceilene]

@karlhorky Thanks so much for opening a PR! I'll get this triaged for review ✨

[shati-patel]

Thank you, @karlhorky! Your change looks good.

Thanks also for including a link to the Heroku deployment in your PR description—that's always helpful 😃

[github-actions]

Thanks very much for contributing! Your pull request has been merged 🎉 You should see your changes appear on the site in approximately 24 hours.

[karlhorky]

Great, glad to help @shati-patel ! Thanks for the merge!