fix(install): Update install command to use new release URL format

[markdalgleish]

As of v3.2.0, html-sketchapp has a new release URL format which breaks our install command. This PR updates the logic for generating the download URL, and also updates the minimum supported version to v3.2.0 in our package.json.

(Ping @kdzwinel)

Update: Also had to update the snapshots to match the latest version of html-sketchapp.

[kdzwinel]

Ouch, sorry for that. Didn't realize someone depends on the file name. I'll be writing down release process instructions this week (@burakukula will be publishing next release), so I'll make sure that "name plugin file correctly" is on the list.

[markdalgleish]

@kdzwinel Would it be too much trouble to start publishing the compiled Sketch plugin to npm again? That was by far the easiest from the perspective of this tool, since it didn't require an extra download step from GitHub.

Alternatively, is there a better way for us to provide a painless install process?

[kdzwinel]

@markdalgleish I didn't want to keep build artifacts in the repo or artificially inflate NPM package size, but if it makes it much easier for you we can start including it again when deploying to NPM.

[markdalgleish]

Yeah, I don't want to force you to bloat up your npm package. I guess the main thing is that the plugin release process is automated so that we can depend on it to be consistent across releases. Is this the case already?

[kdzwinel]

Not really automated (can we automate creation of a GH release?), but it's on the release checklist, so you can be fairly sure we will remember about it. I'm starting to think though that it might be a good idea to put it back on npm - html-sketchapp/html-sketchapp#121