Add Bundler 2.4 blog post and release notes

[deivid-rodriguez]

What was the end-user problem that led to this PR?

The problem was the we should announce the upcoming Bundler 2.4 release.

What is your fix for the problem, implemented in this PR?

My fix is to draft a release blog post and a "What's new" page.

[olleolleolle]

Thanks for making this nice post!

[deivid-rodriguez]

Thanks so much for copy editing! ❤️

[olleolleolle]

Right, I found a small thing.

[olleolleolle]

🏆 Yes!!!

[deivid-rodriguez]

Blog post draft is here: https://bundler-site-bundler-2--j2zpxa.herokuapp.com/blog/2022/12/22/bundler-v2-4.html

I left the section about gems with Rust extensions empty because I think @simi wanted to write about this.

What's new page is here: https://bundler-site-bundler-2--j2zpxa.herokuapp.com/v2.4/whats_new.html.

[deivid-rodriguez]

I moved additional changes to other PRs to make reviewing this one easier.

[simi]

Blog post draft is here: https://bundler-site-bundler-2--j2zpxa.herokuapp.com/blog/2022/12/22/bundler-v2-4.html

I left the section about gems with Rust extensions empty because I think @simi wanted to write about this.

What's new page is here: https://bundler-site-bundler-2--j2zpxa.herokuapp.com/v2.4/whats_new.html.

I have prepared initial version at #982.

[tnir]

@deivid-rodriguez What is the blocker for merging this?

[deivid-rodriguez]

I'm finishing up a fix to bundle lock --update --bundler command, which is currently advertised in the blog post.

I want it to work fine before we publish the post, but if we are willing to publish this right now, I can edit the blog post to remove the mention to it and publish it.

[tnir]

Thanks @deivid-rodriguez. If you do not want to publish this blog post, I am still inclined to publish Bundler v2.4-based docs (https://bundler.io/v2.4/docs.html) as soon as possible. To do so, we can create another PR from this but without changes in /source/blog. What do you think?

[deivid-rodriguez]

Sounds good, let me extract a separate PR!

[deivid-rodriguez]

I extracted #991.

[tnir]

#1051 might be relevant to this once it is merged.

[deivid-rodriguez]

Preview looks good, so let's publish this!