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/query/channels/participants/specialize_test.go

@@ -0,0 +1,58 @@
+package participants
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/telegram/message/peer"
+	"go.mau.fi/mautrix-telegram/pkg/gotd/tg"
+)
+
+func TestElem(t *testing.T) {
+	entities := peer.NewEntities(
+		map[int64]*tg.User{10: {}},
+		map[int64]*tg.Chat{},
+		map[int64]*tg.Channel{},
+	)
+
+	type results struct {
+		admin, creator, photos bool
+	}
+	tests := []struct {
+		Name string
+		Part tg.ChannelParticipantClass
+		results
+	}{
+		{"UnknownPlain", &tg.ChannelParticipant{UserID: 45}, results{}},
+		{"UnknownBanned", &tg.ChannelParticipantBanned{Peer: &tg.PeerUser{UserID: 45}},
+			results{}},
+		{"UnknownAdmin", &tg.ChannelParticipantAdmin{UserID: 45}, results{}},
+		{"UnknownCreator", &tg.ChannelParticipantCreator{UserID: 45}, results{}},
+		{"Plain", &tg.ChannelParticipant{UserID: 10}, results{photos: true}},
+		{"Banned", &tg.ChannelParticipantBanned{Peer: &tg.PeerUser{UserID: 10}},
+			results{photos: true}},
+		{"Admin", &tg.ChannelParticipantAdmin{UserID: 10}, results{
+			admin:  true,
+			photos: true,
+		}},
+		{"Creator", &tg.ChannelParticipantCreator{UserID: 10}, results{
+			creator: true,
+			photos:  true,
+		}},
+	}
+	for _, test := range tests {
+		t.Run(test.Name, func(t *testing.T) {
+			a := require.New(t)
+			var ok bool
+
+			elem := Elem{Participant: test.Part, Entities: entities}
+			_, ok = elem.UserPhotos(nil)
+			a.Equal(test.photos, ok)
+			_, _, ok = elem.Admin()
+			a.Equal(test.admin, ok)
+			_, _, ok = elem.Creator()
+			a.Equal(test.creator, ok)
+		})
+	}
+}