message: Add setWallet function for typescript compatibility
  In typescript, getters and setters must accept/return the same type. In order to accept a string, a new function must be made since Matic.wallet is of the type Web3.Account
diff: @@ -95,6 +95,11 @@ export default class Matic {
  this._parentWeb3.eth.accounts.wallet.add(_wallet)
  }
  + setWallet(_wallet) {
  + this._web3.eth.accounts.wallet.add(_wallet)
  + this._parentWeb3.eth.accounts.wallet.add(_wallet)
  + }
  +
  //
  // Actions
  //
  