[pre-commit] Add pre-commit configuration

.pre-commit-config.yaml

+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+-   repo: https://github.com/ambv/black
+    rev: stable
+    hooks:
+    - id: black
+      language_version: python3.6
+-   repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.0.0
+    hooks:
+    -   id: trailing-whitespace
+    -   id: end-of-file-fixer
+    -   id: check-yaml
+        exclude: meta.yaml
+    -   id: check-added-large-files
+    -   id: flake8