fix(updater): only uses DoH to cloudflare+google

- prevent dns plaintext manipulation both the periodic update and when running in cli mode
- possibly higher reliability on poor connections versus UDP
- drop `-dns` flag in update command
- for now no configuration allowed since it makes everything rather complex

internal/updater/resolver/net.go

@@ -1,17 +1,12 @@
 package resolver
 
 import (
-	"context"
 	"net"
 )
 
-func newResolver(resolverAddress string) *net.Resolver {
-	d := net.Dialer{}
-	resolverAddress = net.JoinHostPort(resolverAddress, "53")
+func newResolver(d Dialer) *net.Resolver {
 	return &net.Resolver{
 		PreferGo: true,
-		Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
-			return d.DialContext(ctx, "udp", resolverAddress)
-		},
+		Dial:     d.Dial,
 	}
 }