Docs: Use gutenberg instead of Gutenberg in package name

[shail-mehta]

What?

Used gutenberg instead of Gutenberg in package tags for consistency.

Why? How?

• Used gutenberg instead of Gutenberg in package tags for consistency in below files.

1. lib/class-wp-theme-json-resolver-gutenberg.php
2. lib/class-wp-theme-json-schema-gutenberg.php
3. lib/experimental/posts/load.php

Testing Instructions

1. Open mentioned files
2. See package name.

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Co-authored-by: shail-mehta <shailu25@git.wordpress.org>
Co-authored-by: t-hamano <wildworks@git.wordpress.org>

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[t-hamano]

Thanks for the PR!

Is there a reason why you only updated files in the lib directory? I think there are many other places you could update besides the lib directory.

[shail-mehta]

Apologies, I hadn’t noticed it was also in a different folder. I’ll review and update the PR accordingly.

[shail-mehta]

I have updated PR accordingly. Once you get a chance could you please review it?

[t-hamano]

LGTM 👍