fix(monitoring): Replace unreachable ntp server

Because apple's time servers are officially not to be used for public projects and are also not accessible, they were exchanged for the servers of Google and Cloudflare.

Author: pascalfriedrich

monitor/ntp.go

@@ -21,13 +21,13 @@ var servers = []string{
 	"time6.aliyun.com",
 	"time7.aliyun.com",
 
-	"time1.apple.com",
-	"time2.apple.com",
-	"time3.apple.com",
-	"time4.apple.com",
-	"time5.apple.com",
-	"time6.apple.com",
-	"time7.apple.com",
+	"time.google.com",
+	"time1.google.com",
+	"time2.google.com",
+	"time3.google.com",
+	"time4.google.com",
+	
+	"time.cloudflare.com",
 }
 
 var availIndex = 0