Bump golang.org/x/oauth2

Bumps [golang.org/x/oauth2](https://github.com/golang/oauth2) from 0.0.0-20180821212333-d2e6202438be to 0.12.0.
- [Commits](https://github.com/golang/oauth2/commits/v0.12.0)

---
updated-dependencies:
- dependency-name: golang.org/x/oauth2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

go.mod

@@ -13,6 +13,6 @@ require (
 	github.com/sirupsen/logrus v1.7.0
 	github.com/spf13/cobra v1.0.0
 	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/stretchr/testify v1.7.0
-	golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be
+	github.com/stretchr/testify v1.8.1
+	golang.org/x/oauth2 v0.12.0
 )