@uppy/core: make Meta generic optional (#5330)

packages/@uppy/core/src/Uppy.ts

@@ -371,7 +371,10 @@ const defaultUploadState = {
  * Manages plugins, state updates, acts as an event bus,
  * adds/removes files and metadata.
  */
-export class Uppy<M extends Meta, B extends Body = Record<string, never>> {
+export class Uppy<
+  M extends Meta = Meta,
+  B extends Body = Record<string, never>,
+> {
   static VERSION = packageJson.version
 
   #plugins: Record<string, UnknownPlugin<M, B>[]> = Object.create(null)