Memory leak using `classifyGif` on Node.js

[ExecutionSpeed]

I think we might have to add an image.dispose() to the classifyGif operation to avoid memory leak.

https://github.com/infinitered/nsfwjs/blob/58844e357b5c684ccf8a68f94094e79f0e246b33/src/index.ts#L244-L245

Possibly adding the image.dispose() below here post classify(...) of each frame?

[GantMan]

that makes sense. Would you be so kind as to open a PR?

[ExecutionSpeed]

Sure, I can do that.