v0.3.5 breaks MSRV using matches! macros

[JohnTitor]

I'm not sure if this crate follows MSRV but #491 introduced matches! macros and v0.3.5 has bumped up MSRV (1.41).

[lemmih]

Hi @JohnTitor. As mentioned in the README, criterion supports the last three minor releases of rust. Support for older versions may be dropped without it being considered a breaking change. I'm open to discussing a policy change if this gets in the way of your workflow, though.