add precommit bot (Project-MONAI#340)

Author: wyli

.pre-commit-config.yaml

@@ -0,0 +1,63 @@
+default_language_version:
+  python: python3.8
+
+ci:
+  autofix_prs: true
+  autoupdate_commit_msg: '[pre-commit.ci] pre-commit suggestions'
+  autoupdate_schedule: quarterly
+  # submodules: true
+
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v4.0.1
+    hooks:
+      - id: end-of-file-fixer
+      - id: trailing-whitespace
+      - id: check-yaml
+      - id: check-docstring-first
+      - id: check-executables-have-shebangs
+      - id: check-toml
+      - id: check-case-conflict
+      - id: check-added-large-files
+        args: ['--maxkb=1024']
+      - id: detect-private-key
+
+  #- repo: https://github.com/asottile/pyupgrade
+  #  rev: v2.23.2
+  #  hooks:
+  #    - id: pyupgrade
+  #      args: [--py36-plus]
+  #      name: Upgrade code
+
+  #- repo: https://github.com/asottile/yesqa
+  #  rev: v1.2.3
+  #  hooks:
+  #    - id: yesqa
+  #      name: Unused noqa
+
+  #- repo: https://github.com/PyCQA/isort
+  #  rev: 5.9.3
+  #  hooks:
+  #    - id: isort
+  #      name: Format imports
+
+  # - repo: https://github.com/psf/black
+  #   rev: 21.7b0
+  #   hooks:
+  #     - id: black
+  #       name: Format code
+
+  #- repo: https://github.com/executablebooks/mdformat
+  #  rev: 0.7.8
+  #  hooks:
+  #    - id: mdformat
+  #      additional_dependencies:
+  #        - mdformat-gfm
+  #        - mdformat_frontmatter
+  #      exclude: CHANGELOG.md
+
+  # - repo: https://github.com/PyCQA/flake8
+  #   rev: 3.9.2
+  #   hooks:
+  #     - id: flake8
+  #       name: Check PEP8