build(packaging): remove rehype (angular#42557)

`rehype` dependency is now moved to the `dgeni-package`, thus it can be removed from the main dependencies list

PR Close angular#42557

Author: jakovljevic-mladen

aio/package.json

@@ -156,7 +156,6 @@
     "npm-run-all": "^4.1.5",
     "protractor": "~7.0.0",
     "puppeteer": "9.0.0",
-    "rehype": "^11.0.0",
     "rehype-slug": "^4.0.1",
     "remark": "^12.0.0",
     "remark-html": "^13.0.0",