Add black git pre-commit hook

Author: rocky

.pre-commit-config.yaml

@@ -0,0 +1,12 @@
+repos:
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.0.0
+    hooks:
+    - id: check-merge-conflict
+    - id: debug-statements
+    - id: end-of-file-fixer
+-   repo: https://github.com/psf/black
+    rev: 19.10b0
+    hooks:
+    - id: black
+      language_version: python3