chore(deps): update dependency google-auth to v1.31.0 (#122)

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This PR contains the following updates:

| Package | Change | Age | Adoption | Passing | Confidence |
|---|---|---|---|---|---|
| [google-auth](https://togithub.com/googleapis/google-auth-library-python) | `==1.30.1` -> `==1.31.0` | [![age](https://badges.renovateapi.com/packages/pypi/google-auth/1.31.0/age-slim)](https://docs.renovatebot.com/merge-confidence/) | [![adoption](https://badges.renovateapi.com/packages/pypi/google-auth/1.31.0/adoption-slim)](https://docs.renovatebot.com/merge-confidence/) | [![passing](https://badges.renovateapi.com/packages/pypi/google-auth/1.31.0/compatibility-slim/1.30.1)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://badges.renovateapi.com/packages/pypi/google-auth/1.31.0/confidence-slim/1.30.1)](https://docs.renovatebot.com/merge-confidence/) |

---

### Release Notes

<details>
<summary>googleapis/google-auth-library-python</summary>

### [`v1.31.0`](https://togithub.com/googleapis/google-auth-library-python/blob/master/CHANGELOG.md#&#8203;1310-httpswwwgithubcomgoogleapisgoogle-auth-library-pythoncomparev1302v1310-2021-06-09)

[Compare Source](https://togithub.com/googleapis/google-auth-library-python/compare/v1.30.2...v1.31.0)

##### Features

-   define useful properties on `google.auth.external_account.Credentials` ([#&#8203;770](https://www.github.com/googleapis/google-auth-library-python/issues/770)) ([f97499c](https://www.github.com/googleapis/google-auth-library-python/commit/f97499c718af70d17c17e0c58d6381273eceabcd))

##### Bug Fixes

-   avoid deleting items while iterating ([#&#8203;772](https://www.github.com/googleapis/google-auth-library-python/issues/772)) ([a5e6b65](https://www.github.com/googleapis/google-auth-library-python/commit/a5e6b651aa8ad407ce087fe32f40b46925bae527))

##### [1.30.2](https://www.github.com/googleapis/google-auth-library-python/compare/v1.30.1...v1.30.2) (2021-06-03)

##### Bug Fixes

-   **dependencies:** add urllib3 and requests to aiohttp extra ([#&#8203;755](https://www.github.com/googleapis/google-auth-library-python/issues/755)) ([a923442](https://www.github.com/googleapis/google-auth-library-python/commit/a9234423cb2b69068fc0d30a5a0ee86a599ab8b7))
-   enforce constraints during unit tests ([#&#8203;760](https://www.github.com/googleapis/google-auth-library-python/issues/760)) ([1a6496a](https://www.github.com/googleapis/google-auth-library-python/commit/1a6496abfc17ab781bfa485dc74d0f7dbbe0c44b)), closes [#&#8203;759](https://www.github.com/googleapis/google-auth-library-python/issues/759)
-   session object was never used in aiohttp request ([#&#8203;700](https://www.github.com/googleapis/google-auth-library-python/issues/700)) ([#&#8203;701](https://www.github.com/googleapis/google-auth-library-python/issues/701)) ([09e0389](https://www.github.com/googleapis/google-auth-library-python/commit/09e0389db72cc9d6c5dde34864cb54d717dc0b92))

##### [1.30.1](https://www.github.com/googleapis/google-auth-library-python/compare/v1.30.0...v1.30.1) (2021-05-20)

##### Bug Fixes

-   allow user to customize context aware metadata path in \_mtls_helper ([#&#8203;754](https://www.github.com/googleapis/google-auth-library-python/issues/754)) ([e697687](https://www.github.com/googleapis/google-auth-library-python/commit/e6976879b392508c022610ab3ea2ea55c7089c63))
-   fix function name in signing error message ([#&#8203;751](https://www.github.com/googleapis/google-auth-library-python/issues/751)) ([e9ca25f](https://www.github.com/googleapis/google-auth-library-python/commit/e9ca25fa39a112cc1a376388ab47a4e1b3ea746c))

### [`v1.30.2`](https://togithub.com/googleapis/google-auth-library-python/blob/master/CHANGELOG.md#&#8203;1302-httpswwwgithubcomgoogleapisgoogle-auth-library-pythoncomparev1301v1302-2021-06-03)

[Compare Source](https://togithub.com/googleapis/google-auth-library-python/compare/v1.30.1...v1.30.2)

</details>

---

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language/snippets/api/requirements.txt

@@ -1,3 +1,3 @@
 google-api-python-client==2.6.0
-google-auth==1.30.1
+google-auth==1.31.0
 google-auth-httplib2==0.1.0