Bump black from 21.5b2 to 21.6b0

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>

poetry.lock

@@ -80,7 +80,7 @@ docs = ["sphinx (>=1.6)", "sphinx-bootstrap-theme (>=0.6)"]
 
 [[package]]
 name = "black"
-version = "21.5b2"
+version = "21.6b0"
 description = "The uncompromising code formatter."
 category = "dev"
 optional = false
@@ -620,7 +620,7 @@ testing = ["pytest (>=3.5,!=3.7.3)", "pytest-checkdocs (>=1.2.3)", "pytest-flake
 [metadata]
 lock-version = "1.1"
 python-versions = ">=3.7.0, <3.10"
-content-hash = "4d9054a240b279da990b8038623d8b2025487ef37162f7f7ef4a4ff8cbae872b"
+content-hash = "89da1f7a8ed6f8ea7477ecf9a66086328cce2d50fb2879311fe00d4ee5b04fc3"
 
 [metadata.files]
 ansiwrap = [
@@ -651,8 +651,8 @@ behave = [
     {file = "behave-1.2.6.tar.gz", hash = "sha256:b9662327aa53294c1351b0a9c369093ccec1d21026f050c3bd9b3e5cccf81a86"},
 ]
 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"},
 ]
 cffi = [
     {file = "cffi-1.14.4-cp27-cp27m-macosx_10_9_x86_64.whl", hash = "sha256:ebb253464a5d0482b191274f1c8bf00e33f7e0b9c66405fbffc61ed2c839c775"},

pyproject.toml

@@ -46,7 +46,7 @@ tzlocal = ">2.0, <3.0"   # https://github.com/regebro/tzlocal/blob/master/CHANGE
 [tool.poetry.dev-dependencies]
 behave = "^1.2"
 mkdocs = "^1.0"
-black = {version = "^21.5b2",allow-prereleases = true}
+black = {version = "^21.6b0",allow-prereleases = true}
 toml = ">=0.10"
 pyflakes = ">=2.2.0"
 pytest = ">=6.2"