FrontierEvm issue: atob is not defined

[jiqiang90]

With recently use of FrontierEvm, user might encounter this error:

<ds-sandbox> ERROR not supported ds @substrate/FrontierEvm 
ReferenceError: atob is not defined

This is due to our build command using webpack to build project, and ethersproject are default using esm lib, one of the decode function is using atob.

In order to resolve this issue, you can add script in your project, this will manually change the webpack installation path for ethers package.

https://github.com/subquery/subquery-network-subql-project/pull/31/files