Upgrade internal dependencies to Astro 5

[natemoo-re]

Description

This PR bumps internal dependencies on astro and @astrojs/markdoc to the upcoming Astro 5.0.0 release line (currently beta).

TBD on how this should be released:

• Wait until 5.0.0 is stable and release as a new minor
• Release as a beta of Starlight's next minor

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Latest commit: d3370c8

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[natemoo-re]

Hmm, getting this error related to the MDX renderer move. Might be due to the dependency structure we're using where Starlight depends on the MDX integration directly.

[vite]: Rollup failed to resolve import "@astrojs/mdx/server.js" from "@astro-renderers".

[lilith]

How soon do you think starlight will support Astro 5? I'm wondering how long I should wait to adopt it for a new docs site.

[delucis]

How soon do you think starlight will support Astro 5? I'm wondering how long I should wait to adopt it for a new docs site.

We’re actively working on it, but hard to say exactly. We’re certainly aiming to have a v5 compatible release ready in time for when Astro 5 is stable.