Update mix.exs to allow scrivener_ecto ~> 3.0

[superhawk610]

Recently, ecto made some breaking changes with 3.12.0 and scrivener_ecto was updated accordingly (see here). The scrivener_ecto package was also bumped up to a new major version 3.0, though it's a backwards-compatible change with respect to scrivener_list (see the diff here). In other words, it is safe for this package to now support scrivener_ecto at ~> 1.0 or ~> 2.0 or ~> 3.0, which is what this PR does.

This change is required to allow using scrivener_ecto ~> 3.0 and scrivener_list in the same project, otherwise a dependency conflict is raised.

[dgigafox]

👍🏼 We need this too. Hope to be merged soon

[dcaixinha]

We also need this! Any chance of merging this @stephenmoloney? 🙏

[stephenmoloney]

It's quite a few years since I've been active with Elixir but I've read through the PR description.

And it's reasonable to merge this.

You can reference this in your projects without a publish to mix ?

[olehgerus]

@stephenmoloney, do you have any plans to release it anytime soon?