Bump yarl from 1.6.2 to 1.6.3 (#5247)

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)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/base.txt

@@ -11,4 +11,4 @@ gunicorn==20.0.4
 idna-ssl==1.1.0; python_version<"3.7"
 typing_extensions==3.7.4.3
 uvloop==0.14.0; platform_system!="Windows" and implementation_name=="cpython" and python_version<"3.9" # MagicStack/uvloop#14
-yarl==1.6.2
+yarl==1.6.3