Add rattler and py-rattler to the June and July release post

[baszalmstra]

Adds a rattler section to the post, placed right after conda.

Around a hundred PRs landed in rattler over June and July, and the crates release continuously, so the section is organised by what changed rather than by version. py-rattler 0.24.0 and 0.25.0 both shipped in the window and are covered.

It leads with the solver work, since that is the part every reader gets for free: #2520 moved rattler to resolvo 0.11.1, roughly a 40% cut on the larger solve benchmarks. The four resolvo PRs underneath it are named with a headline number each rather than explained.

Also in there: iOS and Android subdirs (pointing at the draft CEP, conda/ceps#183), CEP 42 channel relations, flexible channel priority, offline mode, the auth middleware rework, CLI additions, and a correctness roundup.

Two things worth your call:

• I added a rattler tag, which is new for this blog. There is no tags.yml in the repo, so nothing else needs declaring.
• Twelve first-time rattler contributors are merged into the community list, taking it from 10 to 22 names. I checked each against their merge history before June. Trim if that is too many.

One caveat: py-rattler 0.24.0's changelog is mostly pre-June work that happened to land in a June release. __cuda_arch, for instance, merged 20 May, the same day the May post went out. Happy to cut that paragraph back to only what was done in the window if you would rather keep the post strictly to June and July.

[kenodegard]

Thanks, @baszalmstra! Two asks so it fits the rest of the post:

• Trim to a handful of themes. The section is currently longer than conda + conda-build combined.
• Match the style. Rest of the post is install snippet + bullets. Let's avoid dense changelog-style blurbs packed with PR links; those belong in the release notes we can link to at the end.

On the May merge / June release caveat for py-rattler 0.24.0: fine to keep. We're announcing releases, not merges. First-time rattler contributors are fine in the community list too.

Glad to see rattler in the release post!

[baszalmstra]

I trimmed it down! Let me know what you think!