[WIP] Fix ban by software version, some other under-hood changes

- Use updated version of upstream go-xmpp + fixes on client-side
- Still waiting for https://github.com/xmppo/go-xmpp/pull/215
- Introduce golangci-lint v2 + fixes

vendor/golang.org/x/net/proxy/direct.go

@@ -0,0 +1,31 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package proxy
+
+import (
+	"context"
+	"net"
+)
+
+type direct struct{}
+
+// Direct implements Dialer by making network connections directly using net.Dial or net.DialContext.
+var Direct = direct{}
+
+var (
+	_ Dialer        = Direct
+	_ ContextDialer = Direct
+)
+
+// Dial directly invokes net.Dial with the supplied parameters.
+func (direct) Dial(network, addr string) (net.Conn, error) {
+	return net.Dial(network, addr)
+}
+
+// DialContext instantiates a net.Dialer and invokes its DialContext receiver with the supplied parameters.
+func (direct) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
+	var d net.Dialer
+	return d.DialContext(ctx, network, addr)
+}