add mypy

mypy.r2.yml

+files:
+    template: ./python/code_quality/mypy/mypy.yml
+    documentation: ./python/code_quality/mypy/README.md
+data:
+    description: "Run mypy on your repository"
+    icon: 💎
+    public: true
+    labels:
+        - Static TypeChecking
+        - Utilities
+        - Code Quality
+        - Python
+        - TypeChecker
+    license: MIT
+    deprecated: false

python/code_quality/mypy/README.md

+## Objective
+
+Run [mypy](https://mypy.readthedocs.io/en/stable/) on your Python code to perform static typing
+checks, ensuring better code reliability and readability. `mypy` is a Python tool that checks the
+types of variables, function return values, and more.
+
+### Global Configuration of mypy
+
+To add configuration to `mypy` shared with any other usage of mypy (such as manual run, pre-commit,
+etc), you can use `mypy.ini`, `setup.cfg` or `pyproject.toml` configuration file. Learn more
+about [mypy configuration](https://mypy.readthedocs.io/en/stable/config_file.html) files.
+
+## How to use it
+
+1. Configure the `mypy.ini`, `setup.cfg` or `pyproject.toml` file in your repository's root directory with your
+   desired rules.
+2. Include the mypy template in your CI/CD configuration (see quick use above).
+3. If you need to customize the job, check
+   the [jobs customization](https://docs.r2devops.io/get-started/use-templates/#job-templates-customization).
+
+## Add a <a href="https://mypy.readthedocs.io/"><img alt="Type Checked: mypy" src="https://img.shields.io/badge/mypy-checks-blue"></a> Badge to your project README.md
+
+To display the use of mypy in your project, you can add the following badge to your README.md:
+
+```markdown
+<a href="https://mypy.readthedocs.io/">
+    <img alt="Type Checked: mypy" src="https://img.shields.io/badge/mypy-checks-blue">
+</a>
+```

python/code_quality/mypy/mypy.yml

+mypy:
+    image: python:latest
+    stage: code_quality
+    script:
+        - python --version  # Debug
+        - python -m venv venv --upgrade-deps || python -m venv venv  # upgrade-deps is not supported before 3.9
+        - source venv/bin/activate
+        - pip install mypy
+        - mypy
+    only:
+        changes:
+            - ./**/*.py
+            - .gitlab-ci.yml
+            - pyproject.toml