Replace ethereum.org's product roadmap URL on /about page

[tmsko]

Updated the roadmap link so it correctly points to the 2024 roadmap.
Based on the issue #11390

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[nhsz]

LGTM, thanks!

[gitpoap-bot]

Congrats, your important contribution to this open-source project has earned you a GitPOAP!

Be sure to join the Ethereum.org discord if you are interested in contributing further to the project or have any questions for the team.

GitPOAP: 2024 Ethereum.org Contributor:

Head to gitpoap.io & connect your GitHub account to mint!

Learn more about GitPOAPs here.

[isabelladebrito]

Hi @tmsko, thanks again for contributing to ethereum.org!

Besides GitPOAP, you're also eligible to claim an "onchain achievement token" (also known as "OAT") on Galxe 🏅

Here's how you can claim:

1. Head over to https://galxe.com/ethereumorg/campaign/GCBctt4BkX
2. We have already assigned you a role on ethereum.org's Discord server, from where you should be able to claim your OAT on Galxe
3. Connect your wallet and Discord user
4. Check the OAT(s) you're eligible to claim et voilà! 

If you have any questions, don't hesitate to reply to this comment or reach out to me via ethereum.org's Discord server. Cheers!