feat: report which t8n tool ethereum-specs branch & ref in the resolver's response

[danceratopz]

EEST fixtures include an _info section that reports which t8n filled the test (filling-transition-tool).

       "_info": {
            "hash": "0xccce1a34e74cdf5855efd8d2ff1d17b9158c2fdfc6638ae577df92885030a789",
            "comment": "`execution-spec-tests` generated test",
            "filling-transition-tool": "ethereum-spec-evm-resolver 0.0.1",
            "description": "Test function documentation:\n\n    Validate that create2 return data does not interfere with previously existing memory",
            "url": "https://github.com/ethereum/execution-spec-tests/blob/b39d74e9f612c53a1f161e7a765d14a7930c8dcf/tests/constantinople/eip1014_create2/test_create_returndata.py#L19",
            "reference-spec": "https://github.com/ethereum/EIPs/blob/master/EIPS/eip-1014.md",
            "reference-spec-version": "0a3c1015a07958523bb3ef48c2f230c9ba9605d9"
        }

It would be helpful, when EEST fills with EELS, if the fixtures could report the resolved t8n tool, i.e., the branch and ref that was used to fill in this field.