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), [@shikijs/engine-oniguruma](https://github.com/shikijs/shiki/tree/HEAD/packages/engine-oniguruma) and [shiki](https://github.com/shikijs/shiki/tree/HEAD/packages/shiki).


Updates `@shikijs/core` from 3.7.0 to 3.8.1
- [Release notes](https://github.com/shikijs/shiki/releases)
- [Commits](https://github.com/shikijs/shiki/commits/v3.8.1/packages/core)

Updates `@shikijs/engine-javascript` from 3.7.0 to 3.8.1
- [Release notes](https://github.com/shikijs/shiki/releases)
- [Commits](https://github.com/shikijs/shiki/commits/v3.8.1/packages/engine-javascript)

Updates `@shikijs/engine-oniguruma` from 3.7.0 to 3.8.1
- [Release notes](https://github.com/shikijs/shiki/releases)
- [Commits](https://github.com/shikijs/shiki/commits/v3.8.1/packages/engine-oniguruma)

Updates `shiki` from 3.7.0 to 3.8.1
- [Release notes](https://github.com/shikijs/shiki/releases)
- [Commits](https://github.com/shikijs/shiki/commits/v3.8.1/packages/shiki)

---
updated-dependencies:
- dependency-name: "@shikijs/core"
  dependency-version: 3.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: mdx
- dependency-name: "@shikijs/engine-javascript"
  dependency-version: 3.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: mdx
- dependency-name: "@shikijs/engine-oniguruma"
  dependency-version: 3.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: mdx
- dependency-name: shiki
  dependency-version: 3.8.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: mdx
...

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

Author: dependabot[bot]

packages/rehype-shiki/package.json

@@ -13,12 +13,12 @@
     "test:unit": "cross-env NODE_NO_WARNINGS=1 node --experimental-test-coverage --experimental-test-module-mocks --test \"**/*.test.mjs\""
   },
   "dependencies": {
-    "@shikijs/core": "^3.7.0",
-    "@shikijs/engine-javascript": "^3.7.0",
-    "@shikijs/engine-oniguruma": "^3.7.0",
+    "@shikijs/core": "^3.8.1",
+    "@shikijs/engine-javascript": "^3.8.1",
+    "@shikijs/engine-oniguruma": "^3.8.1",
     "classnames": "catalog:",
     "hast-util-to-string": "^3.0.1",
-    "shiki": "~3.7.0",
+    "shiki": "~3.8.1",
     "unist-util-visit": "^5.0.0"
   },
   "devDependencies": {