Bump black from 21.8b0 to 21.9b0 (#989)

Bumps [black](https://github.com/psf/black) from 21.8b0 to 21.9b0.
- [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

@@ -72,7 +72,7 @@ testing = ["pytest (>=4.6)", "pytest-flake8", "pytest-cov", "pytest-black (>=0.3
 
 [[package]]
 name = "black"
-version = "21.8b0"
+version = "21.9b0"
 description = "The uncompromising code formatter."
 category = "dev"
 optional = false
@@ -969,7 +969,7 @@ pyinstall = ["poethepoet", "pyinstaller", "pyinstaller-versionfile", "tomli"]
 [metadata]
 lock-version = "1.1"
 python-versions = "^3.9"
-content-hash = "ef2d1841e949cf7c6819bf01b458de143f5cab798e3eab5b343bf5e5d1fa390a"
+content-hash = "a7ae51da62162e83bd872e2f3abf422056f0b431e11aea4a49577d0777cd4598"
 
 [metadata.files]
 alabaster = [
@@ -1000,8 +1000,8 @@ babelgladeextractor = [
     {file = "backports.entry_points_selectable-1.1.0.tar.gz", hash = "sha256:988468260ec1c196dab6ae1149260e2f5472c9110334e5d51adcb77867361f6a"},
 ]
 black = [
-    {file = "black-21.8b0-py3-none-any.whl", hash = "sha256:2a0f9a8c2b2a60dbcf1ccb058842fb22bdbbcb2f32c6cc02d9578f90b92ce8b7"},
-    {file = "black-21.8b0.tar.gz", hash = "sha256:570608d28aa3af1792b98c4a337dbac6367877b47b12b88ab42095cfc1a627c2"},
+    {file = "black-21.9b0-py3-none-any.whl", hash = "sha256:380f1b5da05e5a1429225676655dddb96f5ae8c75bdf91e53d798871b902a115"},
+    {file = "black-21.9b0.tar.gz", hash = "sha256:7de4cfc7eb6b710de325712d40125689101d21d25283eed7e9998722cf10eb91"},
 ]
 certifi = [
     {file = "certifi-2021.5.30-py2.py3-none-any.whl", hash = "sha256:50b1e4f8446b06f41be7dd6338db18e0990601dce795c2b1686458aa7e8fa7d8"},

pyproject.toml

@@ -53,7 +53,7 @@ pytest = "^6.2"
 pytest-cov = "^2.12"
 pytest-mock = "^3.6.1"
 pytest-runner = "^5.3"
-black = "^21.8b0"
+black = "^21.9b0"
 mypy = "0.910"
 pre-commit = "^2.15"
 sphinx = "^4.1"