Added support of "startapp" deep links with "appname" param (#1651)

* Added "startapp" deep link support

* Remove link_type param, added create_startapp_link method

* Write tests for create_startapp_link method

* Refactor with black & isort

* Added CHANGELOG

* Added support of direct mini app links

* Added CHANGELOG

tests/test_utils/test_deep_linking.py

@@ -52,6 +52,10 @@ class TestDeepLinking:
         link = await create_startapp_link(bot, payload)
         assert link == f"https://t.me/tbot?startapp={payload}"
 
+    async def test_get_startapp_link_with_app_name(self, bot: MockedBot, payload: str):
+        link = await create_startapp_link(bot, payload, app_name="app")
+        assert link == f"https://t.me/tbot/app?startapp={payload}"
+
     async def test_filter_encode_and_decode(self, payload: str):
         encoded = encode_payload(payload)
         decoded = decode_payload(encoded)
@@ -102,6 +106,17 @@ class TestDeepLinking:
 
         assert link == f"https://t.me/tbot?startapp={encoded_payload}"
 
+    async def test_get_startapp_link_with_app_name_and_encoding(
+        self, bot: MockedBot, wrong_payload: str
+    ):
+        # define link
+        link = await create_startapp_link(bot, wrong_payload, encode=True, app_name="app")
+
+        # define reference link
+        encoded_payload = encode_payload(wrong_payload)
+
+        assert link == f"https://t.me/tbot/app?startapp={encoded_payload}"
+
     async def test_64_len_payload(self, bot: MockedBot):
         payload = "p" * 64
         link = await create_start_link(bot, payload)