Don't check MSRV for ash-examples

[Friz64]

ash-examples has a lot of dependencies (mostly through winit), and so it's not unlikely for it to break the MSRV check. Here's the current CI error:

error: package `half v2.4.0` cannot be built because it requires rustc 1.70 or newer, while the currently active rustc version is 1.69.0
Either upgrade to rustc 1.70 or newer, or use
cargo update -p half@2.4.0 --precise ver
where `ver` is the latest version of `half` supporting rustc 1.69.0

It doesn't make much sense to have our MSRV influenced by it IMO.

[MarijnS95]

1c9e422 don't think there was a compelling reason back then, besides "it adheres to it now".

[MarijnS95]

Turns out I intended to land this via #799 in c3d2dd1 too :)