@uppy/core: add missing requiredMetaFields key in restrictions (#4819)

packages/@uppy/core/types/index.d.ts

@@ -154,6 +154,7 @@ export interface Restrictions {
   maxNumberOfFiles?: number | null
   minNumberOfFiles?: number | null
   allowedFileTypes?: string[] | null
+  requiredMetaFields?: string[]
 }
 
 export interface UppyOptions<