deps: bump minimum icu version to 64

Bump minimum version of ICU needed to build node to 64.

Refs: v8/v8@ccbe3d0

Backport-PR-URL: #28005
PR-URL: #27375
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Ujjwal Sharma <usharma1998@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

Author: targos

tools/icu/icu_versions.json

@@ -1,3 +1,3 @@
 {
-    "minimum_icu": 63
+    "minimum_icu": 64
 }