chore(deps-dev): bump flake8-docstrings from 1.5.0 to 1.6.0

Bumps [flake8-docstrings](https://gitlab.com/pycqa/flake8-docstrings) from 1.5.0 to 1.6.0.
- [Release notes](https://gitlab.com/pycqa/flake8-docstrings/tags)
- [Changelog](https://gitlab.com/pycqa/flake8-docstrings/blob/master/HISTORY.rst)
- [Commits](https://gitlab.com/pycqa/flake8-docstrings/compare/1.5.0...1.6.0)

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

requirements-dev.txt

@@ -19,9 +19,7 @@ astroid==2.5.1
 asttokens==2.0.4
     # via flake8-aaa
 astunparse==1.6.3
-    # via
-    #   -r docs/requirements.txt
-    #   pytkdocs
+    # via -r docs/requirements.txt
 attrs==20.3.0
     # via
     #   flake8-bugbear
@@ -51,9 +49,7 @@ botocore==1.20.30
     #   boto3
     #   s3transfer
 cached-property==1.5.2
-    # via
-    #   -r docs/requirements.txt
-    #   pytkdocs
+    # via -r docs/requirements.txt
 certifi==2020.12.5
     # via
     #   -r docs/requirements.txt
@@ -105,7 +101,7 @@ flake8-comprehensions==3.3.1
     # via -r requirements-dev.in
 flake8-debugger==4.0.0
     # via -r requirements-dev.in
-flake8-docstrings==1.5.0
+flake8-docstrings==1.6.0
     # via -r requirements-dev.in
 flake8-eradicate==1.0.0
     # via -r requirements-dev.in
@@ -181,18 +177,6 @@ importlib-metadata==3.7.3
     # via
     #   -r docs/requirements.txt
     #   -r requirements.txt
-    #   argcomplete
-    #   flake8
-    #   flake8-comprehensions
-    #   flake8-simplify
-    #   flake8-typing-imports
-    #   markdown
-    #   pep517
-    #   pluggy
-    #   pre-commit
-    #   pytest
-    #   stevedore
-    #   virtualenv
 iniconfig==1.1.1
     # via pytest
 isort==5.7.0
@@ -466,18 +450,14 @@ tqdm==4.59.0
 typed-ast==1.4.2
     # via
     #   -r docs/requirements.txt
-    #   astroid
     #   black
-    #   flake8-annotations
     #   mypy
 typing-extensions==3.7.4.3
     # via
     #   -r docs/requirements.txt
     #   -r requirements.txt
     #   black
-    #   importlib-metadata
     #   mypy
-    #   pytkdocs
 urllib3==1.26.4
     # via
     #   -r docs/requirements.txt
@@ -502,7 +482,6 @@ zipp==3.4.1
     #   -r docs/requirements.txt
     #   -r requirements.txt
     #   importlib-metadata
-    #   pep517
 
 # The following packages are considered to be unsafe in a requirements file:
 pip==21.0.1