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/mtproto/message_id_test.go

@@ -0,0 +1,25 @@
+package mtproto
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/proto"
+)
+
+func TestClientNewMessageID(t *testing.T) {
+	c := newTestClient(nil)
+	now := c.clock.Now()
+	id := proto.MessageID(c.newMessageID())
+	assert.Equal(t, proto.MessageFromClient, id.Type())
+
+	lag := id.Time().Sub(now)
+	if lag < 0 {
+		lag *= -1
+	}
+	if lag > time.Second {
+		t.Error("generated id lags in time")
+	}
+}