fix(scripts): consistently use caret version when updating dependencies both in package.json and in npm scripts

[gribnoysup]

Le Roux ran into an interesting issue when trying to bump @leafygreen-ui/lib just one minor version up that was causing the update-dependencies script (or just a normal npm install) to fail on the last step with the following error:

npm error code EOVERRIDE
npm error Override for @leafygreen-ui/lib@15.3.0 conflicts with direct dependency

I traced it back to some slightly unexpected behavior in npm internals. Usually if you'd run npm install library@version, if version doesn't contain a range of any sort, npm will install specified version and add it to package.json with a caret: "library": "^version". Before it does that though, it runs a check against overrides field in package.json, and the version spec must match exactly what's in there for it to pass. In this case 15.3.0 that we are trying to install would not be equal to ^15.3.0 even if it's a matching range and will end up in the package.json in the same form and npm fails.

The fix is quite straightforward: just make sure that we consistently use caret range everywhere in the update script.