Add Base mainnet (8453)

[mdehoog]

Add New Chain 8453

Checklist

• The branch is named as add-chain-<chainId>.
• I haven't modified the chains.json file directly.
• In sourcify-chains.ts file
  • I've set supported: true.
  • I've set monitored: false.
  • I haven't added an rpc field but the one in chains.json is used (if not, please explain why).
• I've added a test in chain-tests.js file.
• test-new-chain test in Circle CI is passing.

_{View in Huly HI-642}

[kuzdogan]

Updated chains.json. Can you please remove the rpc and rebase/merge from staging?

[mdehoog]

Any suggestions on getting tests to pass?

Error: No RPC provider was given for this chain with id 1 and name Ethereum Mainnet

Locally this was resolved by copying .env.dev to .env but don't want to commit that.

[kuzdogan]

I don't know where this has come from. I'll have a look

[mdehoog]

@kuzdogan this is caused by f4d68cf

[kuzdogan]

This was unexpected because the tests were passing on our commits. On external PRs there are no env vars and the rpc of those chains with env var rpcs end up as an empty array, hence the error.

Can you please rebase one last time? Just merged myself