Updates some dependencies

[tylerconstance]

The blockers present in @zemccartney's writeup in #267 are still present, though it looks like there's an open PR for that issue now on that project, so hopefully we'll be able to update webpack in another maintenance cycle or two.

Running npx npm-check-updates -m resulted in this list:

 babel-jest            26.x.x  →   27.x.x     
 copy-webpack-plugin   ^6.0.3  →   ^9.0.0     
 dotenv                ^8.2.0  →  ^10.0.0     
 html-webpack-plugin    4.x.x  →    5.x.x     
 jest                  26.x.x  →   27.x.x     
 webpack                4.x.x  →    5.x.x     
 history              ^4.10.1  →   ^5.0.0   

dotenv managed to get two major releases in about two weeks, but the only listed breaking change was dropping support for an older version of node that we already don't support in strangeluv.

jest was slightly trickier because it had a significant changelog for version 27. Our simple test didn't initially pass, but changing the testEnvironment to a newer version which supported getVmContext seemed to do the trick.

We were using jest-environment-jsdom-fifteen, and searching for the next logical iteration revealed that jest-environment-jsdom-sixteen was actually deprecated after being integrated into jest v26. Just changing that string from jest-environment-jsdom-fifteen to jest-environment-jsdom seemed to do the trick, though, and our test passes again.

Updating babel-jest to match, now we're left with the un-upgraded list we're familiar with:

 copy-webpack-plugin   ^6.0.3  →  ^9.0.0     
 html-webpack-plugin    4.x.x  →   5.x.x     
 webpack                4.x.x  →   5.x.x     
 history              ^4.10.1  →  ^5.0.0  

[tylerconstance]

I wasn't actually expecting to see package-lock.json in this project since this is usually the starting point for most projects — should I remove this file in this PR?

[devinivy]

I think that's a good idea 👍