[scr_ecto-103] Improve options/configuration described in README

[theirishpenguin]

The Problem

The README does not mention options such as :allow_overflow_page_number and direct configuration such as :max_page_size. This is noted in issue #103

This PR is to (make a start at least) on correcting that.

[theirishpenguin]

One check fails above with the following error...

Is there something I should do to correct this?

(As this is just a documentation change, I'm conscious it's probably best if I don't go messing with the actual codebase as part of this PR 😄 )

[theirishpenguin]

A fellow Elixir-er kindly helped me out with the build issue at https://github.com/theirishpenguin/scrivener_ecto/pull/1/files

Looking at that PR, it seems like there is an issue building scrivener_ecto with elixir: '1.15.0' / otp: '26.0.1'. I guess that this means that an update will be needed for scrivener_ecto to keep it building on otp: '26.0.1'. I might open an issue on this repo to call this out explicitly. (Given the Low Maintenance warning on this repo, I guess you won't have time to work on this actively @drewolson - which is understandable).

[cpjolicoeur]

@theirishpenguin We have updated the master branch of Scrivener_Ecto to support OTP 26. If you want to rebase your PR work here off the current master, we can look at getting these documentation changes in.

[theirishpenguin]

@cpjolicoeur Thanks 🙌

I've just rebased this PR now off the current master.

[theirishpenguin]

I have tried to kick off the build again with a "reinitialise checks" commit, but it seems like that needs approval from a maintainer.

(I did have a few problems with that commit - all fixed now - so maybe that is why it requires manual approval).

Is it possible for someone to kick off a build on this PR?