Task: Update Dates & Links in `README.md`

[nelsonic]

At the time of opening this issue, the README.md refers to the 2022 SO Survey:
https://github.com/dwyl/technology-stack/tree/df28b38a2962bc286bcd5131ca8fa1d63be2b90e

and:

As noted in: dwyl/learn-elixir#102 (comment) the 2025 (most recent) survey Elixir, Phoenix and Postgres are still in the most desireable.

Todo

• Update the README.md to reflect the most recent data. ⤴️
• Make any other relevant updates. ⏳
• Collapse Table of Contents
• Update diagram: https://docs.google.com/drawings/d/12IpbIHRDL0dXXf3pWUo6YWh0lGQ7y-YmQ1Slk4GqIeo/edit

[nelsonic]

@iteles just to keep you informed, I'm doing this NOW. 🧑‍💻 📝 ⏳
So that I can offload most of the "hard sell" on Elixir/Phoenix to here 🔗
instead of having it in the proposal. ✂️ 👌

It might feel like a procrastination / side-quest / detour, 🙄
but I've already linked to this doc. 🔗
So sadly, it must be up-to-date ⬆️
else it looks baaaaad ... 🙈

[nelsonic]

PR: #166