refactor: call toString on numerical values to be bee-js compatible (#148)

* refactor: call toString on numerical values to be bee-js compatible

* feat: add upload size check

package.json

@@ -24,7 +24,7 @@
     "url": "https://github.com/ethersphere/bee-dashboard.git"
   },
   "dependencies": {
-    "@ethersphere/bee-js": "^0.10.0",
+    "@ethersphere/bee-js": "^0.12.0",
     "@material-ui/core": "^4.11.4",
     "@material-ui/icons": "^4.11.2",
     "@material-ui/lab": "^4.0.0-alpha.57",