Add: Add README for mypy-python action

mypy-python/README.md

@@ -0,0 +1,35 @@
+# Mypy Python Action
+
+GitHub Action to check typings in Python project with [mypy].
+
+## Example
+
+```yml
+name: Type checking
+
+on:
+  pull_request:
+
+jobs:
+  lint-python:
+    name: Setup and lint project
+    runs-on: ubuntu-latest
+    steps:
+        - uses: greenbone/actions/mypy-python@v2
+          with:
+            packages: my_project tests
+```
+
+## Action Configuration
+
+|Input Variable|Description| |
+|--------------|-----------|-|
+| packages | Python packages to check | Required |
+| mypy-arguments | Additional arguments to mypy | Optional |
+| python-version | Python version to use for running the action. | Optional (default is `3.10`) |
+| poetry-version | Use a specific poetry version. By default the latest release is used. | Optional (default latest poetry version) |
+| cache | Cache dependencies by setting it to `"true"`. Leave unset or set to an other string then `"true"` to disable the cache. | Optional |
+| cache-dependency-path | Used to specify the path to dependency files. Supports wildcards or a list of file names for caching multiple dependencies. | Optional |
+| cache-poetry-installation | "Cache poetry and its dependencies. Default is `"true"`. Set to an other string then `"true"` to disable the cache." | Optional (default: `"true"`) |
+
+[mypy]: https://mypy.readthedocs.io/en/stable/