Add extra requirements

.readthedocs.yml

@@ -10,5 +10,4 @@ python:
   install:
     - method: pip
       path: .
-      extra_requirements:
-        - docs
+    - requirements: docs2/requirements.txt

aiogram/api/types/downloadable.py

@@ -1,4 +1,7 @@
-from typing_extensions import Protocol
+try:
+    from typing import Protocol
+except ImportError:  # pragma: no cover
+    from typing_extensions import Protocol  # type: ignore
 
 
 class Downloadable(Protocol):

pyproject.toml

@@ -40,6 +40,7 @@ aiofiles = "^0.4.0"
 uvloop = {version = "^0.14.0", markers = "sys_platform == 'darwin' or sys_platform == 'linux'", optional = true}
 async_lru = "^1.0"
 aiohttp-socks = {version = "^0.3.8", optional = true}
+typing-extensions = {version = "^3.7.4", python = "<3.8"}
 
 [tool.poetry.dev-dependencies]
 uvloop = {version = "^0.14.0", markers = "sys_platform == 'darwin' or sys_platform == 'linux'"}
@@ -77,7 +78,6 @@ sphinx-rtd-theme = "^0.4.3"
 [tool.poetry.extras]
 fast = ["uvloop"]
 proxy = ["aiohttp-socks"]
-docs = ['sphinx-intl', 'typing-extensions']
 
 [tool.black]
 line-length = 99