upgrade aiohttp to major new version: 2 (#2609)

frameworks/Python/aiohttp/requirements.txt

@@ -1,10 +1,10 @@
-aiohttp==1.3.1
+aiohttp==2.0.2
 aiohttp-jinja2==0.13.0
 aiopg==0.13.0
-asyncpg==0.8.4
-cchardet==1.1.2
-gunicorn==19.6.0
-psycopg2==2.6.2
-SQLAlchemy==1.1.5
+asyncpg==0.9.0
+cchardet==1.1.3
+gunicorn==19.7.1
+psycopg2==2.7.1
+SQLAlchemy==1.1.6
 ujson==1.35
-uvloop==0.7.2
+uvloop==0.8.0