Fix link to "Good First Review" issues in README

[mcliwanow]

What?

This PR fixes URL of the "Good First Review" link. Previously, it pointed to open issues with label "Good First Issue". After changes it's pointing to open reviews with label "Good First Review".

Why?

I was going through docs for contributors and when I clicked the "Good First Review" link I noticed it took me to the wrong page so I decided to fix it. It's not a biggie and I hope to contribute in a more meaningful way in the future :)

How?

Nothing fancy, just updated URL of the link in README file.

Testing Instructions

1. Check if the link to "Good First Review" filter works correctly from Github:

• Go to https://github.com/mcliwanow/gutenberg/blob/fix/link-to-good-first-review/docs/contributors/code/README.md (updated README file)
• Click the "Good First Review" link
• Verify that you are taken to open reviews for the Gutenberg repository and that label "Good First Review" is selected

2. If your IDE support Previewing .md files then:

• Checkout branch from this PR on your machine
• Open file docs/contributors/code/README.md in Preview mode
• Click the "Good First Review" link
• Verify that you are taken to open reviews for the Gutenberg repository and that label "Good First Review" is selected

[github-actions]

👋 Thanks for your first Pull Request and for helping build the future of Gutenberg and WordPress, @mcliwanow! In case you missed it, we'd love to have you join us in our Slack community, where we hold regularly weekly meetings open to anyone to coordinate with each other.

If you want to learn more about WordPress development in general, check out the Core Handbook full of helpful information.

[skorasaurus]

Thanks for your effort; the good first review link should be for pull requests and go to https://github.com/WordPress/gutenberg/pulls?q=is%3Aopen+is%3Apr+label%3A%22Good+First+Review%22

[mcliwanow]

the good first review link should be for pull requests and go to https://github.com/WordPress/gutenberg/pulls?q=is%3Aopen+is%3Apr+label%3A%22Good+First+Review%22

I feel a little bit embarrassed now 😬 😉 Thanks for pointing that out @skorasaurus ! I have updated code and PR description accordingly.

[fabiankaegy]

Tested the new link and it works as expected :) Thanks for your contribution! :)

[github-actions]

Congratulations on your first merged pull request, @mcliwanow! We'd like to credit you for your contribution in the post announcing the next WordPress release, but we can't find a WordPress.org profile associated with your GitHub account. When you have a moment, visit the following URL and click "link your GitHub account" under "GitHub Username" to link your accounts:

https://profiles.wordpress.org/me/profile/edit/

And if you don't have a WordPress.org account, you can create one on this page:

https://login.wordpress.org/register

Kudos!