chore(deps): update dependency sinon to v12 (#281)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [sinon](https://sinonjs.org/) ([source](https://togithub.com/sinonjs/sinon)) | [`^11.0.0` -> `^12.0.0`](https://renovatebot.com/diffs/npm/sinon/11.1.2/12.0.1) | [![age](https://badges.renovateapi.com/packages/npm/sinon/12.0.1/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/npm/sinon/12.0.1/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/npm/sinon/12.0.1/compatibility-slim/11.1.2)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/npm/sinon/12.0.1/confidence-slim/11.1.2)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

<details>
<summary>sinonjs/sinon</summary>

### [`v12.0.1`](https://togithub.com/sinonjs/sinon/blob/master/CHANGES.md#&#8203;1201)

[Compare Source](https://togithub.com/sinonjs/sinon/compare/v12.0.0...v12.0.1)

-   [`3f598221`](https://togithub.com/sinonjs/sinon/commit/3f598221045904681f2b3b3ba1df617ed5e230e3)
    Fix issue with npm unlink for npm version > 6 (Carl-Erik Kopseng)
    > 'npm unlink' would implicitly unlink the current dir
    > until version 7, which requires an argument
-   [`51417a38`](https://togithub.com/sinonjs/sinon/commit/51417a38111eeeb7cd14338bfb762cc2df487e1b)
    Fix bundling of cjs module ([#&#8203;2412](https://togithub.com/sinonjs/sinon/issues/2412)) (Julian Grinblat)
    > -   Fix bundling of cjs module
    >
    > -   Run prettier

*Released by [Carl-Erik Kopseng](https://togithub.com/fatso83) on 2021-11-04.*

#### 12.0.0

### [`v12.0.0`](https://togithub.com/sinonjs/sinon/compare/v11.1.2...v12.0.0)

[Compare Source](https://togithub.com/sinonjs/sinon/compare/v11.1.2...v12.0.0)

</details>

---

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packages/google-cloud-documentai/package.json

@@ -43,7 +43,7 @@
     "mocha": "^8.0.0",
     "null-loader": "^4.0.0",
     "pack-n-play": "^1.0.0-2",
-    "sinon": "^11.0.0",
+    "sinon": "^12.0.0",
     "ts-loader": "^9.0.0",
     "typescript": "^3.8.3",
     "webpack": "^5.0.0",