Update @oclif/plugin-help in group pkg to the latest version � (#1069)

Summary:
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## The dependency [oclif/plugin-help](https://github.com/oclif/plugin-help) was updated from `2.2.3` to `3.0.0`.
This version is **not covered** by your **current version range**.

If you don’t accept this pull request, your project will work just like it did before. However, you might be missing out on a bunch of new features, fixes and/or performance improvements from the dependency update.

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**Publisher:** [chadian](https://www.npmjs.com/~chadian)
**License:** MIT

[Find out more about this release](https://github.com/oclif/plugin-help).

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Your [Greenkeeper](https://greenkeeper.io) bot 🌴
Pull Request resolved: https://github.com/facebook/flipper/pull/1069

Reviewed By: nikoant

Differential Revision: D21278324

Pulled By: passy

fbshipit-source-id: 6217e4d078341d15795b454b47b3ce482a0bfeeb

desktop/pkg/package.json

@@ -15,7 +15,7 @@
     "@oclif/command": "^1",
     "@oclif/config": "^1",
     "@oclif/parser": "^3",
-    "@oclif/plugin-help": "^2",
+    "@oclif/plugin-help": "^3.0.0",
     "@oclif/plugin-warn-if-update-available": "^1.7.0",
     "ajv": "^6.12.2",
     "ajv-errors": "^1.0.1",