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/crypto/encrypted_message_test.go

@@ -0,0 +1,30 @@
+package crypto
+
+import (
+	"math/big"
+	"testing"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/bin"
+)
+
+func TestEncryptedMessage_Encode(t *testing.T) {
+	k, ok := big.NewInt(0).SetString(`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`, 16)
+	if !ok {
+		t.Fatal(ok)
+	}
+
+	payload := []byte{1, 2, 3, 4}
+
+	var authKey Key
+	k.FillBytes(authKey[:])
+
+	d := EncryptedMessage{
+		EncryptedData: payload,
+		MsgKey:        bin.Int128{0, 0, 0, 0},
+		AuthKeyID:     authKey.ID(),
+	}
+	b := new(bin.Buffer)
+	if err := d.Encode(b); err != nil {
+		t.Fatal(err)
+	}
+}