net/dns/resolver: use correct Cloudflare DoH hostnames

We were using the wrong ones for the malware & adult content
variants. Docs:

https://developers.cloudflare.com/1.1.1.1/1.1.1.1-for-families/setup-instructions/dns-over-https

Earlier commit which added them:
236eb4d04d

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

net/dns/resolver/forwarder.go

@@ -519,16 +519,16 @@ func init() {
 	addDoH("2606:4700:4700::1001", "https://cloudflare-dns.com/dns-query")
 
 	// Cloudflare -Malware
-	addDoH("1.1.1.2", "https://cloudflare-dns.com/dns-query")
-	addDoH("1.0.0.2", "https://cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1112", "https://cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1002", "https://cloudflare-dns.com/dns-query")
+	addDoH("1.1.1.2", "https://security.cloudflare-dns.com/dns-query")
+	addDoH("1.0.0.2", "https://security.cloudflare-dns.com/dns-query")
+	addDoH("2606:4700:4700::1112", "https://security.cloudflare-dns.com/dns-query")
+	addDoH("2606:4700:4700::1002", "https://security.cloudflare-dns.com/dns-query")
 
 	// Cloudflare -Malware -Adult
-	addDoH("1.1.1.3", "https://cloudflare-dns.com/dns-query")
-	addDoH("1.0.0.3", "https://cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1113", "https://cloudflare-dns.com/dns-query")
-	addDoH("2606:4700:4700::1003", "https://cloudflare-dns.com/dns-query")
+	addDoH("1.1.1.3", "https://family.cloudflare-dns.com/dns-query")
+	addDoH("1.0.0.3", "https://family.cloudflare-dns.com/dns-query")
+	addDoH("2606:4700:4700::1113", "https://family.cloudflare-dns.com/dns-query")
+	addDoH("2606:4700:4700::1003", "https://family.cloudflare-dns.com/dns-query")
 
 	// Google
 	addDoH("8.8.8.8", "https://dns.google/dns-query")