pre-commit checks for black+isort

.pre-commit-config.yaml

@@ -0,0 +1,10 @@
+repos:
+- repo: https://github.com/psf/black
+  rev: '21.12b0'
+  hooks:
+    - id: black
+
+- repo: https://github.com/timothycrosley/isort
+  rev: '5.10.1'
+  hooks:
+    - id: isort

CONTRIBUTE.rst

@@ -27,6 +27,7 @@ will be run against any commits to the project.
 #. Activate it: `source ~/virtualenv/troposphere/bin/activate`
 #. `pip install --upgrade pip setuptools wheel`
 #. `pip install -r requirements-dev.txt`
+#. `pre-commit install`
 #. Run tests
     1. `pycodestyle .`
     #. `pyflakes .`

requirements-dev.txt

@@ -19,6 +19,7 @@ pycodestyle>=2.4
 pydocstyle>=3.0
 pyflakes>=2.1
 pylint>=1.9
+pre-commit>=2.16
 
 # ---- ---- Testing
 pytest>=4.1