Increase MSRV to 1.81.0

[alamb]

Which issue does this PR close?

Rationale for this change

Per the policy: https://github.com/apache/datafusion?tab=readme-ov-file#rust-version-compatibility-policy

DataFusion's supports the last 4 stable Rust minor versions released and any such versions released within the last 4 months.

The most recent versions are 1.81, 1.82, 1.83, 1.84
https://github.com/rust-lang/rust/blob/master/RELEASES.md

• Related to chore(deps): bump home from 0.5.9 to 0.5.11 in /datafusion-cli #14257

Several of our dependencies now have a MSRV of 1.81

What changes are included in this PR?

Update MSRV to 1.81

Are these changes tested?

Are there any user-facing changes?

[comphead]

Thanks @alamb
we also need to change it in

datafusion-cli/Dockerfile

And here .devcontainer/Dockerfile looks like the version is missing which doesn't seem to be correct imho as it takes latest rustc

[alamb]

Thanks everyone; I want to merge this in to unblock a bunch of the other dependency upgrades. I will make a follow on PR to change this one:

Thanks @alamb
we also need to change it in

datafusion-cli/Dockerfile

• Update in Update version in datafusion-cli/Dockerfile to 1.81 #14344

[alamb]

And here .devcontainer/Dockerfile looks like the version is missing which doesn't seem to be correct imho as it takes latest rustc

BTW @comphead I think using the latest Rust in the dev container makes sense -- there is no reason why it needs to use the oldest rust supported by DataFusion (the MSRV)

Perhaps we should actually change the DataFusion CLI dockerfile the same way 🤔