fix(starters): update gatsby monorepo (#12896)

This PR contains the following updates:

| Package | Type | Update | Change | References |
|---|---|---|---|---|
| gatsby | dependencies | patch | [`^2.3.2` -> `^2.3.3`](https://diff.intrinsic.com/gatsby/2.3.2/2.3.3) | [source](https://togithub.com/gatsbyjs/gatsby) |
| gatsby-plugin-manifest | dependencies | patch | [`^2.0.24` -> `^2.0.25`](https://diff.intrinsic.com/gatsby-plugin-manifest/2.0.24/2.0.25) | [source](https://togithub.com/gatsbyjs/gatsby) |
| gatsby-plugin-sharp | dependencies | patch | [`^2.0.31` -> `^2.0.32`](https://diff.intrinsic.com/gatsby-plugin-sharp/2.0.31/2.0.32) | [source](https://togithub.com/gatsbyjs/gatsby) |

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### Release Notes

<details>
<summary>gatsbyjs/gatsby</summary>

### [`v2.3.3`](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.3.2...gatsby@2.3.3)

[Compare Source](https://togithub.com/gatsbyjs/gatsby/compare/gatsby@2.3.2...gatsby@2.3.3)

</details>

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package.json

@@ -13,7 +13,7 @@
     "test": "echo \"Write tests! -> https://gatsby.dev/unit-testing\""
   },
   "dependencies": {
-    "gatsby": "^2.3.2",
+    "gatsby": "^2.3.3",
     "react": "^16.8.5",
     "react-dom": "^16.8.5"
   },