Set `current` protocol to Lima

Motivation and Context

Lima has been activated, and it's now the current protocol.

Description

This MR changes current to Lima in protocols.ml. Examples have been adapted accordingly.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Performance improvement (non-breaking change that improves performance)
• None (change with no changelog)

Changelog

By default, Lima protocol is used as current. This affects compilation of certain primitives (such as Tezos.create_ticket and contracts using chest, see changelog for Lima protocol introduction for more information).

Kathmandu can still be used passing the flag --protocol kathmandu.

Checklist:

• Changes follow the existing coding style (use dune @fmt to check).
• Tests for the changes have been added (for bug fixes / feature).
• Documentation has been updated.
• Changelog description has been added (if appropriate).
• Start titles under ## Changelog section with #### (if appropriate).
• There is no image or uploaded file in changelog
• Examples in changed behaviour have been added to the changelog (for breaking change / feature).