Please upgrade polkadot libs

[h4x3rotab]

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 <anonymous> (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.