fix: source-maps find their designated source (#2435)

fix: source-maps find their designate source

We weren't including the `src` folder in the files published too npm.
This caused errors such as the following seen in the sandbox and by
users on discord.

```
WARNING in ./node_modules/xrpl/dist/npm/utils/xrpConversion.js
Module Warning (from ./node_modules/source-map-loader/dist/cjs.js):
Failed to parse source map from '/sandbox/node_modules/xrpl/src/utils/xrpConversion.ts' file: Error: ENOENT: no such file or directory, open '/sandbox/node_modules/xrpl/src/utils/xrpConversion.ts'
```

packages/ripple-keypairs/package.json

@@ -10,7 +10,8 @@
     "prepublish": "npm run lint && npm test"
   },
   "files": [
-    "dist/*"
+    "dist/*",
+    "src/*"
   ],
   "main": "dist/",
   "directories": {