Bumped Slick to version 3.6.1 and Play-slick to version 5.4.0

[odisseus]

I had to remove support for Scala 2.12 because newer versions of Slick don't support it.

See also slick/slick#2698, slick/slick#3233

[Copilot]

Pull Request Overview

This PR upgrades Slick from version 3.4.1 to 3.6.1 and Play-slick from version 5.1.0 to 5.4.0, along with dropping support for Scala 2.12 as newer Slick versions no longer support it.

• Updated dependency versions for Slick (3.4.1 → 3.6.1) and Play-slick (5.1.0 → 5.4.0)
• Removed Scala 2.12 support from build configuration and CI workflow
• Added custom MappedTo implementation to replace deprecated Slick functionality

Reviewed Changes

Copilot reviewed 12 out of 13 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
project/Dependencies.scala	Updates Slick and Play-slick versions along with test dependencies
project/Settings.scala	Removes Scala 2.12 from cross-compilation targets
.github/workflows/scala.yml	Removes Scala 2.12 from CI matrix
unicorn-core/src/main/scala/org/virtuslab/unicorn/MappedTo.scala	Adds custom MappedTo implementation with isomorphism support
unicorn-core/src/main/scala/org/virtuslab/unicorn/IsomorphicColumnTypeConversion.scala	Provides column type conversion utilities
unicorn-core/src/main/scala/org/virtuslab/unicorn/Identifiers.scala	Removes import of deprecated Slick MappedTo
Multiple test files	Updates ID classes to extend MappedToBase and adds isomorphic conversion imports
unicorn-play/src/main/scala/org/virtuslab/unicorn/UnicornPlay.scala	Updates database type reference
unicorn-core/src/test/scala/org/virtuslab/unicorn/BaseTest.scala	Updates database type reference

[Copilot]

Using println for error reporting in library code is not recommended. Consider using a proper logging framework or removing this debug statement.

[Copilot]

The error message indicates this is a workaround and states users should not see it, which could be confusing if they do encounter it. Consider providing a more helpful error message.

Suggested change

	c.abort(c.enclosingPosition, "Work-around for SI-8351 leading to illegal macro-invocation -- You should not see this message")
	c.abort(c.enclosingPosition, "Invalid macro invocation: The type parameter must extend MappedToBase. Please ensure that your type definition satisfies this requirement.")

[Copilot]

This class lacks documentation explaining its purpose and usage. Consider adding a scaladoc comment describing how it provides column type conversion for isomorphic types.

Suggested change

	/**
	* Provides column type conversion for isomorphic types in Slick.
	*
	* This class enables the mapping of two types that are isomorphic (i.e., they can be converted
	* back and forth without loss of information) to be used as column types in a database schema.
	*
	* @param profile The Slick `JdbcProfile` used for database interaction.
	* @example
	* Given an isomorphism between types `A` and `B`, you can define a column type for `A`:
	* {{{
	* implicit val columnTypeForA: BaseColumnType[A] =
	* new IsomorphicColumnTypeConversion().isomorphicType[A, B]
	* }}}
	*/