build(deps): bump the next group with 2 updates

Bumps the next group with 2 updates: [next](https://github.com/vercel/next.js) and [eslint-config-next](https://github.com/vercel/next.js/tree/HEAD/packages/eslint-config-next).


Updates `next` from 14.2.15 to 15.0.3
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v14.2.15...v15.0.3)

Updates `eslint-config-next` from 14.2.15 to 15.0.3
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/commits/v15.0.3/packages/eslint-config-next)

---
updated-dependencies:
- dependency-name: next
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: next
- dependency-name: eslint-config-next
  dependency-type: direct:development
  update-type: version-update:semver-major
  dependency-group: next
...

Signed-off-by: dependabot[bot] <[email protected]>

packages/next/package.json

@@ -25,7 +25,7 @@
     "@content-collections/core": "0.x"
   },
   "devDependencies": {
-    "next": "^14.2.15",
+    "next": "^15.0.3",
     "tsup": "^8.2.4",
     "typescript": "^5.5.4",
     "@content-collections/core": "workspace:*"