add difficulty bomb delay to eip 858

[cslarson]

When opening a pull request to submit a new EIP, please use the suggested template: https://github.com/ethereum/EIPs/blob/master/eip-X.md

We have a GitHub bot that automatically merges some PRs. It will merge yours immediately if certain criteria are met:

• The PR edits only existing draft PRs.
• The build passes.
• Your Github username or email address is listed in the 'author' header of all affected PRs, inside .
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[eip-automerger]

Hi! I'm a bot, and I wanted to automerge your PR, but couldn't because of the following issue(s):

• File assets/eip-858/calculations.md is not an EIP
• EIP 858 requires approval from one of (cslarson@gmail.com)

[5chdn]

You are delaying it by 6 million blocks, so this is rather ~3 years.

[cslarson]

Thanks for the feedback. I've amended now to reflect a delay of 2m blocks, or roughly a year.

[ghost]

Haha this is great 👍