AVRO-3868: [Rust][CI] Check consistency between the doc comment in lib.rs and README.md

[sarutak]

AVRO-3868

What is the purpose of the change

This PR proposes to add a consistency check between the doc comment in avro/src/lib.rs and avro/README.md.
AVRO-3849 added cargo-rdme so it's nice if we can check the consistency between them.

Verifying this change

Done by GitHub Actions.

Documentation

• Does this pull request introduce a new feature? (no)

[martin-g]

The change looks good but installing cargo-rdme takes 5 mins ... This makes the CI 5 mins slower ...
I wonder how useful this is. Most of the users use docs.rs. An out-of-date README.md is not a big deal.

[sarutak]

I wonder how useful this is. Most of the users use docs.rs. An out-of-date README.md is not a big deal.

I think an out-of-date README.md is not a big deal too but an out-of-date doc.rs is an issue.
It really happened before 7ff2d7a.

Making CI slower is indeed not good so how about caching cargo-rdme?

[martin-g]

Making CI slower is indeed not good so how about caching cargo-rdme?

That would be OK!

[sarutak]

cargo-rdme seems to be cached as expected.
https://github.com/apache/avro/actions/runs/6266491283/job/17017596658?pr=2510#step:6:16

[martin-g]

Thank you, @sarutak !