Please upgrade polkadot libs

**Describe the bug**

Cannot pay the bounty in Polkadot or Kusama. After clicking pay button it give out the follow error:

```
instrument.ts:129 2021-08-10 18:23:50 REGISTRY: Error: Unable to create Enum via index 13, in V0, V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12
at c (core.min.6981819684dd.js:19)
at d (core.min.6981819684dd.js:19)
at l (core.min.6981819684dd.js:19)
at core.min.6981819684dd.js:19
at new v (core.min.6981819684dd.js:19)
at new (core.min.6981819684dd.js:19)
at new r (core.min.6981819684dd.js:19)
at r.decodeU8a (core.min.6981819684dd.js:19)
at o (core.min.6981819684dd.js:19)
at new u (core.min.6981819684dd.js:19)
at new b (core.min.6981819684dd.js:19)
at f (core.min.6981819684dd.js:19)
at new o (core.min.6981819684dd.js:19)
at f (core.min.6981819684dd.js:19)
at o (core.min.6981819684dd.js:19)
at r.RpcCore._formatOutput (core.min.6981819684dd.js:19)
at o (core.min.6981819684dd.js:19)
```

I think an upgrade of `@polkadot/api` dependencies can fix the problem. In PR #8269 the library was minimized and included in gitcoin. So I think a fix is to just redo the similar thing.