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/_example/rsagen_empty_test.go

@@ -0,0 +1,24 @@
+// Code generated by rsagen, DO NOT EDIT.
+
+package example
+
+import (
+	"crypto/rsa"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"go.mau.fi/mautrix-telegram/pkg/gotd/crypto"
+)
+
+func TestFingerprintEmptyPK(t *testing.T) {
+	fingerprint := func(pubkey *rsa.PublicKey) string {
+		return fmt.Sprintf("%08x", uint64(crypto.RSAFingerprint(pubkey)))
+	}
+	expected := []string{}
+	assert.Len(t, EmptyPK, len(expected))
+	for i, pubkey := range EmptyPK {
+		assert.Equal(t, expected[i], fingerprint(pubkey))
+	}
+}