[intl] Bump the ICU required version to 68.

roll node-ci in https://chromium-review.googlesource.com/c/v8/node-ci/+/2547360

Bug: chromium:1138555
Change-Id: I894f47023ea45493d94a107ca22038a54543fc6c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2543263
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Shu-yu Guo <syg@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71286}

src/objects/intl-objects.h

@@ -21,7 +21,7 @@
 #include "unicode/locid.h"
 #include "unicode/uversion.h"
 
-#define V8_MINIMUM_ICU_VERSION 67
+#define V8_MINIMUM_ICU_VERSION 68
 
 namespace U_ICU_NAMESPACE {
 class BreakIterator;