Bump golang.org/x/oauth2 from 0.19.0 to 0.20.0 (#9)

Bumps [golang.org/x/oauth2](https://github.com/golang/oauth2) from 0.19.0 to 0.20.0.
- [Commits](golang/oauth2@v0.19.0...v0.20.0)

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

go.mod

@@ -4,8 +4,11 @@ go 1.16
 
 require (
 	github.com/google/go-github/v35 v35.0.0
+	github.com/kr/pretty v0.3.0 // indirect
+	github.com/rogpeppe/go-internal v1.9.0 // indirect
 	github.com/stretchr/testify v1.8.1
 	go.uber.org/multierr v1.11.0
 	golang.org/x/crypto v0.17.0 // indirect
-	golang.org/x/oauth2 v0.19.0
+	golang.org/x/oauth2 v0.20.0
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 )