Update Google samples to latest OAuth endpoints (#189)

Author: Eric Koleda

samples/CloudIdentityAwareProxy.gs

@@ -54,7 +54,7 @@ function getService() {
   return OAuth2.createService('CloudIAP')
       // Set the endpoint URLs.
       .setAuthorizationBaseUrl('https://accounts.google.com/o/oauth2/auth')
-      .setTokenUrl('https://www.googleapis.com/oauth2/v4/token')
+      .setTokenUrl('https://oauth2.googleapis.com/token')
 
       // Set the client ID and secret.
       .setClientId(CLIENT_ID)

samples/Google.gs

@@ -41,8 +41,8 @@ function reset() {
 function getService() {
   return OAuth2.createService('Google')
       // Set the endpoint URLs.
-      .setAuthorizationBaseUrl('https://accounts.google.com/o/oauth2/auth')
-      .setTokenUrl('https://accounts.google.com/o/oauth2/token')
+      .setAuthorizationBaseUrl('https://accounts.google.com/o/oauth2/v2/auth')
+      .setTokenUrl('https://oauth2.googleapis.com/token')
 
       // Set the client ID and secret.
       .setClientId(CLIENT_ID)

samples/GoogleHangoutsChat.gs

@@ -63,7 +63,7 @@ function reset() {
 function getChatbotService() {
   return OAuth2.createService('MyChatBot')
       // Set the endpoint URL.
-      .setTokenUrl('https://accounts.google.com/o/oauth2/token')
+      .setTokenUrl('https://oauth2.googleapis.com/token')
 
       // Set the private key and issuer.
       .setPrivateKey(PRIVATE_KEY)

samples/GoogleServiceAccount.gs

@@ -44,7 +44,7 @@ function reset() {
 function getService() {
   return OAuth2.createService('GoogleDrive:' + USER_EMAIL)
       // Set the endpoint URL.
-      .setTokenUrl('https://accounts.google.com/o/oauth2/token')
+      .setTokenUrl('https://oauth2.googleapis.com/token')
 
       // Set the private key and issuer.
       .setPrivateKey(PRIVATE_KEY)