Bump golang.org/x/oauth2

Bumps [golang.org/x/oauth2](https://github.com/golang/oauth2) from 0.0.0-20210220000619-9bb904979d93 to 0.13.0.
- [Commits](https://github.com/golang/oauth2/commits/v0.13.0)

---
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>

go.mod

@@ -7,34 +7,22 @@ require (
 	github.com/fatih/color v1.10.0 // indirect
 	github.com/fsnotify/fsnotify v1.4.9 // indirect
 	github.com/go-sql-driver/mysql v1.5.0
-	github.com/golang/protobuf v1.4.3 // indirect
-	github.com/google/go-cmp v0.5.4 // indirect
 	github.com/google/go-github/v32 v32.1.0
 	github.com/gopherjs/gopherjs v0.0.0-20200217142428-fce0ec30dd00 // indirect
 	github.com/gorilla/mux v1.8.0
 	github.com/jmoiron/sqlx v1.3.1
-	github.com/kr/text v0.2.0 // indirect
 	github.com/lib/pq v1.8.0 // indirect
 	github.com/magiconair/properties v1.8.5 // indirect
 	github.com/mattn/go-runewidth v0.0.9 // indirect
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/mitchellh/mapstructure v1.4.1 // indirect
-	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/pelletier/go-toml v1.9.0 // indirect
 	github.com/smartystreets/assertions v1.2.0 // indirect
-	github.com/spf13/afero v1.6.0 // indirect
 	github.com/spf13/cast v1.3.1 // indirect
 	github.com/spf13/cobra v1.1.3
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/spf13/viper v1.7.1
-	github.com/stretchr/testify v1.7.0
-	golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83 // indirect
-	golang.org/x/net v0.0.0-20210226172049-e18ecbb05110 // indirect
-	golang.org/x/oauth2 v0.0.0-20210220000619-9bb904979d93
-	golang.org/x/sys v0.0.0-20210503173754-0981d6026fa6 // indirect
-	golang.org/x/text v0.3.6 // indirect
-	google.golang.org/appengine v1.6.7 // indirect
-	gopkg.in/check.v1 v1.0.0-20200902074654-038fdea0a05b // indirect
+	github.com/stretchr/testify v1.8.1
+	golang.org/x/oauth2 v0.13.0
 	gopkg.in/ini.v1 v1.62.0 // indirect
-	gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776 // indirect
 )