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/session/tdesktop/md5_test.go

@@ -0,0 +1,24 @@
+package tdesktop
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_tdesktopMD5(t *testing.T) {
+	tests := []struct {
+		input, output string
+	}{
+		{"data", "D877F783D5D3EF8C18D5027F940662CD"},
+		{"data#1", "438B3BB129B86F4E9CA19D4CDF58C398"},
+		{"data#2", "A7FDF864FBC10B7772ADA161AE3C900E"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			a := require.New(t)
+			a.Equal(tt.output, tdesktopMD5(tt.input))
+			a.Equal(tt.output[:16], fileKey(tt.input))
+		})
+	}
+}