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/cmd/rsagen/main_test.go

@@ -0,0 +1,27 @@
+//go:build linux
+
+package main
+
+import (
+	"os"
+	"testing"
+
+	"github.com/rogpeppe/go-internal/testscript"
+)
+
+func TestMain(m *testing.M) {
+	os.Exit(testscript.RunMain(m, map[string]func() int{
+		"rsagen": func() int {
+			if err := run(); err != nil {
+				return 1
+			}
+			return 0
+		},
+	}))
+}
+
+func TestScript(t *testing.T) {
+	testscript.Run(t, testscript.Params{
+		Dir: "testdata",
+	})
+}