Add benchmark for deepcopy

[eendebakpt]

One python method that is currently not in the pyperformance benchmarks is deepcopy. This PRs adds a benchmark that tests performance of deepcopy on a nested dictionary and a dataclass.

The dictionary and dataclass have been chosen as example of structures can are often copied and then modified. (e.g. passing configuration settings to a method that modifies one of the settings before passing it on)

Fixes#199

[ericsnowcurrently]

This looks mostly good. Aside from a few linting issues, there are only a couple small concerns.

[eendebakpt]

This looks mostly good. Aside from a few linting issues, there are only a couple small concerns.

@ericsnowcurrently Changes made.

[ericsnowcurrently]

Thanks, @eendebakpt. I'll take a look as soon as I can.

[ericsnowcurrently]

Mostly LGTM. There are a few really minor things that I won't even bother mentioning. 😄 The only thing worth looking at is the overhead of everything going on the in the various loops in the one benchmark. My recommendation doesn't impact readability all that much so you might as well apply it, just in case.

[ericsnowcurrently]

LGTM

[ericsnowcurrently]

Thanks for the benchmark, @eendebakpt!