Update ZZC manifest to 0.6.4.

manifests/ZZC.json

@@ -8,8 +8,8 @@
   "manualUrl": "https://zzc-cv.github.io",
   "sourceUrl": "https://github.com/zezic/ZZC",
   "donateUrl": "https://paypal.me/zezic",
-  "repoVersion": "0.6.3",
-  "latestVersion": "0.6.3",
+  "repoVersion": "0.6.4",
+  "latestVersion": "0.6.4",
   "buildTimestamp": 1557407256,
   "status": "available"
 }