Bump golang.org/x/oauth2 from 0.17.0 to 0.21.0 (#47)

Bumps [golang.org/x/oauth2](https://github.com/golang/oauth2) from 0.17.0 to 0.21.0.
- [Commits](golang/oauth2@v0.17.0...v0.21.0)

---
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>

Author: dependabot[bot]

go.mod

@@ -4,10 +4,12 @@ go 1.15
 
 require (
 	github.com/getsentry/sentry-go v0.28.0
+	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
 	github.com/google/go-github/v53 v53.2.0
 	github.com/julienschmidt/httprouter v1.3.0
 	github.com/narqo/go-badge v0.0.0-20190124110329-d9415e4e1e9f
+	github.com/rogpeppe/go-internal v1.9.0 // indirect
 	github.com/rs/cors v1.11.0
 	golang.org/x/image v0.10.0 // indirect
-	golang.org/x/oauth2 v0.17.0
+	golang.org/x/oauth2 v0.21.0
 )