Bump attrs from 20.1.0 to 21.2.0

Bumps [attrs](https://github.com/python-attrs/attrs) from 20.1.0 to 21.2.0.
- [Release notes](https://github.com/python-attrs/attrs/releases)
- [Changelog](https://github.com/python-attrs/attrs/blob/main/CHANGELOG.rst)
- [Commits](python-attrs/attrs@20.1.0...21.2.0)

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

Author: dependabot-preview[bot]

requirements.txt

@@ -1,5 +1,5 @@
 appdirs==1.4.4
-attrs==20.1.0
+attrs==21.2.0
 boto3==1.14.45
 chardet==3.0.4
 dependency-injector==3.23.2

setup.py

@@ -25,7 +25,7 @@
         ],
     },
     install_requires=[
-        "attrs==20.1.0",
+        "attrs==21.2.0",
         "appdirs==1.4.4",
         "boto3==1.14.45",
         "chardet==3.0.4",