internal: add microsoft sandbox token endpoint to brokenAuthHeaders list

microsoft is now requiring oauth logins to sandbox accounts for bingads

https://docs.microsoft.com/en-us/bingads/guides/migration-guide?view=bingads-12

the token endpoint is login.live-int.com

https://docs.microsoft.com/en-us/bingads/guides/authentication-oauth?view=bingads-12

Change-Id: Ic0c1d8a358d549b747f59e826f02a95d0247f86a
GitHub-Last-Rev: f2a5d0a8124950db1f8aac6d9652ea87028e5d21
GitHub-Pull-Request: golang/oauth2#329
Reviewed-on: https://go-review.googlesource.com/c/139357
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/internal/token.go b/internal/token.go
index 5c5451a..711bc93 100644
--- a/internal/token.go
+++ b/internal/token.go
@@ -110,6 +110,7 @@
 	"https://login.salesforce.com/",
 	"https://login.windows.net",
 	"https://login.live.com/",
+	"https://login.live-int.com/",
 	"https://oauth.sandbox.trainingpeaks.com/",
 	"https://oauth.trainingpeaks.com/",
 	"https://oauth.vk.com/",