move gotd fork into repo. (#111)

- update to latest telegram layer
- remove some references to fields in tg.Entities that don't exist in
the schema
- originally added here:
https://github.com/beeper/td/commit/820929062a2ba0104397bc01235ab58a9cff780e
  - referenced here
-
https://github.com/mautrix/telegramgo/commit/124f0967ed195b5a380c9bd02e170ada9710dde3
-
https://github.com/mautrix/telegramgo/commit/4205047aab2e0639217148b5d125bfaab668bd8e

pkg/gotd/telegram/mtproxy_example_test.go

@@ -0,0 +1,58 @@
+package telegram_test
+
+import (
+	"context"
+	"encoding/hex"
+	"fmt"
+	"os"
+	"os/signal"
+
+	"github.com/go-faster/errors"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/dcs"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+func connectViaMTProxy(ctx context.Context) error {
+	secret, err := hex.DecodeString(os.Getenv("SECRET"))
+	if err != nil {
+		return errors.Wrap(err, "parse secret")
+	}
+
+	resolver, err := dcs.MTProxy(
+		os.Getenv("PROXY_ADDR"),
+		secret,
+		dcs.MTProxyOptions{},
+	)
+	if err != nil {
+		return errors.Wrap(err, "create MTProxy resolver")
+	}
+
+	client, err := telegram.ClientFromEnvironment(telegram.Options{
+		Resolver: resolver,
+	})
+	if err != nil {
+		return errors.Wrap(err, "create client")
+	}
+
+	return client.Run(ctx, func(ctx context.Context) error {
+		cfg, err := tg.NewClient(client).HelpGetConfig(ctx)
+		if err != nil {
+			return errors.Wrap(err, "get config")
+		}
+
+		fmt.Println("This DC: ", cfg.ThisDC)
+		return nil
+	})
+}
+
+func ExampleClient_mtproxy() {
+	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer cancel()
+
+	if err := connectViaMTProxy(ctx); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "%+v\n", err)
+		os.Exit(1)
+	}
+}