fix(typings): update the type of RawData

We could also split the declaration of RawData with the "browser"
field:

```
// for Node.js
export type RawData = string | Buffer | ArrayBuffer | ArrayBufferView; // no Blob
// for the browser
export type RawData = string | ArrayBuffer | ArrayBufferView | Blob; // no Buffer
```

But it does not seem supported by the TypeScript compiler, so we'll
revert to just using "any" for now.

Related: #128

Author: darrachequesne

lib/commons.ts

@@ -26,7 +26,9 @@ export type PacketType =
   | "noop"
   | "error";
 
-export type RawData = string | Buffer | ArrayBuffer | ArrayBufferView | Blob;
+// RawData should be "string | Buffer | ArrayBuffer | ArrayBufferView | Blob", but Blob does not exist in Node.js and
+// requires to add the dom lib in tsconfig.json
+export type RawData = any;
 
 export interface Packet {
   type: PacketType;