Upgrade to aiohttp v3 (lablup/backend.ai-manager#64)

* aiohttp.Timeout is dropped and now it is encouraged to use
  async_timeout directly.

* Requires pnuckowski/aioresponses#87 or pnuckowski/aioresponses#89 to
  be merged.

ai/backend/common/utils.py

@@ -9,6 +9,7 @@
 import uuid
 
 import aiohttp
+from async_timeout import timeout as _timeout
 
 
 def env_info():
@@ -115,7 +116,7 @@ def readable_size_to_bytes(expr):
 async def curl(url, default_value=None, params=None, headers=None, timeout=0.2):
     try:
         async with aiohttp.ClientSession() as sess:
-            with aiohttp.Timeout(timeout):
+            with _timeout(timeout):
                 async with sess.get(url, params=params, headers=headers) as resp:
                     assert resp.status == 200
                     body = await resp.text()

setup.py

@@ -13,7 +13,7 @@ def read_src_version():
 requires = [
     'pyzmq',
     'aiozmq',
-    'aiohttp~=2.3.0',
+    'aiohttp~=3.0.0',
     'aiodns',
     'async_timeout',
     'etcd3~=0.7.0',