Bump attrs from 20.2.0 to 20.3.0 (#390)

dependabot-preview[bot] · web-flow · commit 5eeeb7ccf999 · 2020-11-06T05:47:31.000Z
diff --git a/requirements-dev.txt b/requirements-dev.txt
@@ -1,7 +1,7 @@
 -e .
 aiohttp==3.7.2
 alabaster>=0.6.2
-attrs==20.2.0
+attrs==20.3.0
 coverage==5.3
 flake8==3.8.4
 jinja2==2.11.2
