Fix typo in module file name

Author: t4top

package.json

@@ -15,11 +15,11 @@
   },
   "homepage": "https://github.com/nerdvibe/mina-ledger-js",
   "main": "./dist/index.js",
-  "module": "./dist/index.mjs",
+  "module": "./dist/index.js",
   "types": "./dist/index.d.ts",
   "exports": {
     "require": "./dist/index.js",
-    "import": "./dist/index.mjs",
+    "import": "./dist/index.js",
     "types": "./dist/index.d.ts"
   },
   "repository": {