Delete package-lock.json

we don’t need `@uppy/thumbnail-generator/package-lock.json`, it should be in the root only, right @goto-bus-stop?

packages/@uppy/thumbnail-generator/package-lock.json

@@ -1,13 +0,0 @@
-{
-	"name": "@uppy/thumbnail-generator",
-	"version": "1.5.5",
-	"lockfileVersion": 1,
-	"requires": true,
-	"dependencies": {
-		"exifr": {
-			"version": "4.3.4",
-			"resolved": "https://registry.npmjs.org/exifr/-/exifr-4.3.4.tgz",
-			"integrity": "sha512-1pS43SxlWUy3MGsL7pNaNO6OjStAH0tr/EnqT6BJOhft4xCNsN9QyXdhap71PEF4FIm2CPOyolls8L5h++wHyg=="
-		}
-	}
-}