Bump yarl from 1.6.2 to 1.6.3

Bumps [yarl](https://github.com/aio-libs/yarl) from 1.6.2 to 1.6.3.
- [Release notes](https://github.com/aio-libs/yarl/releases)
- [Changelog](https://github.com/aio-libs/yarl/blob/master/CHANGES.rst)
- [Commits](aio-libs/yarl@v1.6.2...v1.6.3)

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -17,4 +17,4 @@ multidict==5.0.2          # via aiohttp, yarl
 pycares==3.1.1            # via aiodns
 pycparser==2.20           # via cffi
 typing-extensions==3.7.4.3  # via aiohttp
-yarl==1.6.2               # via aiohttp
+yarl==1.6.3               # via aiohttp