Update golang.org/x/oauth2 commit hash to 5d25da1 (#2621)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

go.mod

@@ -47,7 +47,7 @@ require (
 	golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a
 	golang.org/x/image v0.0.0-20200801110659-972c09e46d76
 	golang.org/x/net v0.0.0-20200822124328-c89045814202
-	golang.org/x/oauth2 v0.0.0-20200107190931-bf48bf16ab8d
+	golang.org/x/oauth2 v0.0.0-20200902213428-5d25da1a8d43
 	gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc // indirect
 	gopkg.in/dgrijalva/jwt-go.v3 v3.2.0
 )