Change default scheme in url method to 'https'

[coorasse]

Motivation / Background

It's quite surprising that default schema is http in 2025. I believe it's time to change this to https. I am aware this might be considered a breaking change, but I think is worth it.

Checklist

Before submitting the PR make sure the following are checked:

• This Pull Request is related to one change. Changes that are unrelated 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]
• Tests are added or updated if you fix a bug, refactor something, or add a feature.
• Tests and Rubocop are passing before submitting your proposed changes.

[coorasse]

If you think this is a good PR, I'll go ahead, check the tests and update the docs as well. Thank you for your time!