meta: bump the mdx group with 4 updates

Bumps the mdx group with 4 updates: [@shikijs/core](https://github.com/shikijs/shiki/tree/HEAD/packages/core), [@shikijs/engine-javascript](https://github.com/shikijs/shiki/tree/HEAD/packages/engine-javascript), [shiki](https://github.com/shikijs/shiki/tree/HEAD/packages/shiki) and [remark-reading-time](https://github.com/mattjennings/remark-reading-time).


Updates `@shikijs/core` from 3.3.0 to 3.4.2
- [Release notes](https://github.com/shikijs/shiki/releases)
- [Commits](https://github.com/shikijs/shiki/commits/v3.4.2/packages/core)

Updates `@shikijs/engine-javascript` from 3.3.0 to 3.4.2
- [Release notes](https://github.com/shikijs/shiki/releases)
- [Commits](https://github.com/shikijs/shiki/commits/v3.4.2/packages/engine-javascript)

Updates `shiki` from 3.3.0 to 3.4.2
- [Release notes](https://github.com/shikijs/shiki/releases)
- [Commits](https://github.com/shikijs/shiki/commits/v3.4.2/packages/shiki)

Updates `remark-reading-time` from 2.0.1 to 2.0.2
- [Release notes](https://github.com/mattjennings/remark-reading-time/releases)
- [Commits](mattjennings/remark-reading-time@2.0.1...2.0.2)

---
updated-dependencies:
- dependency-name: "@shikijs/core"
  dependency-version: 3.4.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: mdx
- dependency-name: "@shikijs/engine-javascript"
  dependency-version: 3.4.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: mdx
- dependency-name: shiki
  dependency-version: 3.4.2
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: mdx
- dependency-name: remark-reading-time
  dependency-version: 2.0.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: mdx
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

packages/rehype-shiki/package.json

@@ -11,11 +11,11 @@
     "test:unit": "node --experimental-test-coverage --experimental-test-module-mocks --test \"**/*.test.mjs\""
   },
   "dependencies": {
-    "@shikijs/core": "^3.3.0",
+    "@shikijs/core": "^3.4.2",
     "@shikijs/engine-javascript": "^3.3.0",
     "classnames": "~2.5.1",
     "hast-util-to-string": "^3.0.1",
-    "shiki": "~3.3.0",
+    "shiki": "~3.4.2",
     "unist-util-visit": "^5.0.0"
   }
 }