Update benchmark HTML report generation

[TimJentzsch]

What problem does this solve or what need does it fill?

When running cargo bench, I get the following warning:

WARNING: HTML report generation will become a non-default optional feature in Criterion.rs 0.4.0.
This feature is being moved to cargo-criterion (https://github.com/bheisler/cargo-criterion) and will be optional in a future version of Criterion.rs. To silence this warning, either switch to cargo-criterion or enable the 'html_reports' feature in your Cargo.toml.

What solution would you like?

As explained in the warning, we need to either switch to cargo-criterion or enable the html_reports feature in our Cargo.toml.