Add pre commit

Add pre-commit configuration

Add pre-commit section in the README

depends on !35 (merged)

.pre-commit-config.yaml

+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.2.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+  - repo: https://github.com/psf/black
+    rev: 21.5b0
+    hooks:
+      - id: black
+  - repo: https://github.com/pycqa/flake8
+    rev: 3.9.1
+    hooks:
+      - id: flake8
+  - repo: https://github.com/PyCQA/pylint
+    rev: v2.13.8
+    hooks:
+      - id: pylint