docs: update the Heroku Deployment Guide for v4

[bogdaaamn]

What does it do?

I have walked through the Hosting Proivder Guides > Heroku and install Strapi v4 on a Heroku instance. With some changes in the database.js, I confirm it works well on the v4.

Why is it needed?

I fixed the following issues:

• 48ea380 Update the Postgres config snippet to match the new structure of the connection.connection object. (along with the debug flag 38e6587)
• fd3126a Update localhost broken links to working /developer-docs/ URLs
• 263cb7e Remove the This third-party deployment guide might not be up-to-date with Strapi v4. caution disclaimer from the page

Related issue(s)/PR(s)

n/a

[strapi-cla]

All committers have signed the CLA.

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documentation – ./docs

🔍 Inspect: https://vercel.com/strapijs/documentation/HWxjTqXRyipd6iYLmWA6Q3u2yJUR
✅ Preview: https://documentation-git-fork-bogdaaamn-docs-heroku-de-bc65b5-strapijs.vercel.app

[pwizla]

Thank you very much @bogdaaamn ! I will review it today :-)

[pwizla]

LGTM 🙂 Thank you again for your very first contribution to Strapi docs, @bogdaaamn, we really appreciate it 🤗
It's merged and will be live with the next deployment batch.

[bogdaaamn]

Thanks a lot @pwizla!!