Bump black from 21.5b2 to 21.6b0 (#858)

Bumps [black](https://github.com/psf/black) from 21.5b2 to 21.6b0.
- [Release notes](https://github.com/psf/black/releases)
- [Changelog](https://github.com/psf/black/blob/main/CHANGES.md)
- [Commits](https://github.com/psf/black/commits)

---
updated-dependencies:
- dependency-name: black
  dependency-type: direct:development
...

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

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

poetry.lock

@@ -60,7 +60,7 @@ Babel = "*"
 
 [[package]]
 name = "black"
-version = "21.5b2"
+version = "21.6b0"
 description = "The uncompromising code formatter."
 category = "dev"
 optional = false
@@ -798,7 +798,7 @@ testing = ["pytest (>=4.6)", "pytest-checkdocs (>=1.2.3)", "pytest-flake8", "pyt
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.7"
-content-hash = "f785b64f3fc8fae56467b4bbe3391361b4963977ea035577508642afe30b82c5"
+content-hash = "ee2791f78119c2ecba9b520f70c7a066f6951a1600c7acf7491a3541e6f4d0a0"
 
 [metadata.files]
 alabaster = [
@@ -825,8 +825,8 @@ babelgladeextractor = [
     {file = "BabelGladeExtractor-0.7.0.tar.bz2", hash = "sha256:bcf805e28b4bb18c8b6909a65a7cf5c7c2bcbf4ae50b164878c9682d22271798"},
 ]
 black = [
-    {file = "black-21.5b2-py3-none-any.whl", hash = "sha256:e5cf21ebdffc7a9b29d73912b6a6a9a4df4ce70220d523c21647da2eae0751ef"},
-    {file = "black-21.5b2.tar.gz", hash = "sha256:1fc0e0a2c8ae7d269dfcf0c60a89afa299664f3e811395d40b1922dff8f854b5"},
+    {file = "black-21.6b0-py3-none-any.whl", hash = "sha256:dfb8c5a069012b2ab1e972e7b908f5fb42b6bbabcba0a788b86dc05067c7d9c7"},
+    {file = "black-21.6b0.tar.gz", hash = "sha256:dc132348a88d103016726fe360cb9ede02cecf99b76e3660ce6c596be132ce04"},
 ]
 certifi = [
     {file = "certifi-2020.12.5-py2.py3-none-any.whl", hash = "sha256:719a74fb9e33b9bd44cc7f3a8d94bc35e4049deebe19ba7d8e108280cfd59830"},

pyproject.toml

@@ -49,7 +49,7 @@ pytest = "^6.2"
 pytest-cov = "^2.12"
 pytest-mock = "^3.6.1"
 pytest-runner = "^5.3"
-black = "^21.5b2"
+black = "^21.6b0"
 mypy = "0.902"
 pre-commit = "^2.12"
 sphinx = "^4.0"