Removed useless requirements as the bug they are there to fix has been patched.

requirements.txt

@@ -1,7 +1,5 @@
 git+https://github.com/Rapptz/discord.py@rewrite#egg=discord.py[voice]
-aiohttp<2.3.0,>=2.0.0
 beautifulsoup4==4.6.0
 pillow==5.1.0
 numpy==1.14.3
-yarl<1.2
 youtube_dl