Add pre-commit configuration for black.

To set up, run `pre-commit install`.

.pre-commit-config.yaml

@@ -0,0 +1,6 @@
+repos:
+  - repo: https://github.com/psf/black
+    rev: 20.8b1
+    hooks:
+      - id: black
+        language_version: python3

requirements.txt

@@ -1,10 +1,31 @@
-Pyside2>=5.15.2
-pyinstaller==3.6
-
-Pillow~=7.2.0
-tabulate~=0.8.7
-
+altgraph==0.17
+appdirs==1.4.4
+black==20.8b1
+cfgv==3.2.0
+click==7.1.2
+distlib==0.3.1
+filelock==3.0.12
+future==0.18.2
+identify==1.5.13
+Jinja2==2.11.3
+MarkupSafe==1.1.1
 mypy==0.782
 mypy-extensions==0.4.3
-jinja2>=2.11.2
-shapely==1.7.1
+nodeenv==1.5.0
+pathspec==0.8.1
+pefile==2019.4.18
+Pillow==7.2.0
+pre-commit==2.10.1
+PyInstaller==3.6
+PySide2==5.15.2
+pywin32-ctypes==0.2.0
+PyYAML==5.4.1
+regex==2020.11.13
+Shapely==1.7.1
+shiboken2==5.15.2
+six==1.15.0
+tabulate==0.8.7
+toml==0.10.2
+typed-ast==1.4.2
+typing-extensions==3.7.4.3
+virtualenv==20.4.2