Bump golang.org/x/oauth2 from 0.20.0 to 0.21.0 (#1485)

Bumps [golang.org/x/oauth2](https://github.com/golang/oauth2) from
0.20.0 to 0.21.0.
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/golang/oauth2/commit/5fd42413edb3b1699004a31b72e485e0e4ba1b13"><code>5fd4241</code></a>
google: update compute token refresh</li>
<li>See full diff in <a
href="https://github.com/golang/oauth2/compare/v0.20.0...v0.21.0">compare
view</a></li>
</ul>
</details>
<br />


[![Dependabot compatibility
score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=golang.org/x/oauth2&package-manager=go_modules&previous-version=0.20.0&new-version=0.21.0)](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores)

Dependabot will resolve any conflicts with this PR as long as you don't
alter it yourself. You can also trigger a rebase manually by commenting
`@dependabot rebase`.

[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)

---

<details>
<summary>Dependabot commands and options</summary>
<br />

You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits
that have been made to it
- `@dependabot merge` will merge this PR after your CI passes on it
- `@dependabot squash and merge` will squash and merge this PR after
your CI passes on it
- `@dependabot cancel merge` will cancel a previously requested merge
and block automerging
- `@dependabot reopen` will reopen this PR if it is closed
- `@dependabot close` will close this PR and stop Dependabot recreating
it. You can achieve the same result by closing it manually
- `@dependabot show <dependency name> ignore conditions` will show all
of the ignore conditions of the specified dependency
- `@dependabot ignore this major version` will close this PR and stop
Dependabot creating any more for this major version (unless you reopen
the PR or upgrade to it yourself)
- `@dependabot ignore this minor version` will close this PR and stop
Dependabot creating any more for this minor version (unless you reopen
the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop
Dependabot creating any more for this dependency (unless you reopen the
PR or upgrade to it yourself)


</details>

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

go.mod

@@ -23,7 +23,7 @@ require (
 	github.com/stretchr/testify v1.9.0 // MIT
 	golang.org/x/exp v0.0.0-20240222234643-814bf88cf225
 	golang.org/x/mod v0.18.0
-	golang.org/x/oauth2 v0.20.0
+	golang.org/x/oauth2 v0.21.0
 	golang.org/x/sync v0.7.0
 	golang.org/x/term v0.21.0
 	golang.org/x/text v0.16.0