Bump aiofiles from 0.7.0 to 0.8.0

Bumps [aiofiles](https://github.com/Tinche/aiofiles) from 0.7.0 to 0.8.0.
- [Release notes](https://github.com/Tinche/aiofiles/releases)
- [Commits](Tinche/aiofiles@v0.7.0...v0.8.0)

---
updated-dependencies:
- dependency-name: aiofiles
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -6,7 +6,7 @@
 #
 aiodns==3.0.0
     # via fdiff (setup.py)
-aiofiles==0.7.0
+aiofiles==0.8.0
     # via fdiff (setup.py)
 aiohttp==3.7.4.post0
     # via fdiff (setup.py)