Fix BAD_PATTERN regex in deeplinking process. (#1630)

* add test payload in `test_deep_linking` to demonstrate the bug

* fix the `BAD_PATTERN` regex

* add changes file

CHANGES/1630.bugfix.rst

@@ -0,0 +1 @@
+Fix the regex pattern that finds the "bad characters" for deeplink payload.

aiogram/utils/deep_linking.py

@@ -18,7 +18,7 @@ from aiogram.utils.payload import decode_payload, encode_payload
 if TYPE_CHECKING:
     from aiogram import Bot
 
-BAD_PATTERN = re.compile(r"[^A-z0-9-]")
+BAD_PATTERN = re.compile(r"[^a-zA-Z0-9-_]")
 
 
 async def create_start_link(

tests/test_utils/test_deep_linking.py

@@ -10,12 +10,14 @@ PAYLOADS = [
     "aaBBccDDeeFF5544332211",
     -12345678901234567890,
     12345678901234567890,
+    "underscore_and-dash",
 ]
 WRONG_PAYLOADS = [
     "@BotFather",
     "Some:special$characters#=",
     "spaces spaces spaces",
     1234567890123456789.0,
+    "has`backtick",
 ]