Update bots so they use iOS10 SDK

ios/build/bots/chromium.mac/ios-device-gn.json

Index: ios/build/bots/chromium.mac/ios-device-gn.json
diff --git a/ios/build/bots/chromium.mac/ios-device-gn.json b/ios/build/bots/chromium.mac/ios-device-gn.json
index bcfbe8c3819b6e82ec30984ab51d32ad40c4bca2..74d0b20ea36255e7381ca153668463160f287969 100644
--- a/ios/build/bots/chromium.mac/ios-device-gn.json
+++ b/ios/build/bots/chromium.mac/ios-device-gn.json
@@ -7,7 +7,7 @@
     "Builder for 32-bit devices.",
     "Build is performed with gn+ninja."
   ],
-  "xcode version": "7.0",
+  "xcode version": "8.0",
   "GYP_DEFINES": [
     "OS=ios",
     "chromium_ios_signing=0",
@@ -27,7 +27,7 @@
   "compiler": "ninja",
   "additional_compile_targets": ["gn_all"],
   "configuration": "Release",
-  "sdk": "iphoneos9.0",
+  "sdk": "iphoneos10.0",
   "tests": [
   ]
 }