Upgrade ICU to match master

Author: burmako

utils/update_checkout/update-checkout-config.json

@@ -263,7 +263,7 @@
                 "swift-integration-tests": "swift-DEVELOPMENT-SNAPSHOT-2019-12-02-a",
                 "swift-xcode-playground-support": "swift-DEVELOPMENT-SNAPSHOT-2019-12-02-a",
                 "ninja": "release",
-                "icu": "release-61-1",
+                "icu": "release-65-1",
                 "indexstore-db": "swift-DEVELOPMENT-SNAPSHOT-2019-12-02-a",
                 "sourcekit-lsp": "swift-DEVELOPMENT-SNAPSHOT-2019-12-02-a",
                 "tensorflow": "7c7d924821a8b1b20433c2f3f484bbd409873a84",