chore: set minimum required python version to 3.10

pyproject.toml

@@ -21,7 +21,7 @@ Changelog = 'https://github.com/Festo-se/cyclonedx-editor-validator/releases'
 cdx-ev = "cdxev.__main__:main"
 
 [tool.poetry.dependencies]
-python = "^3.9.0"
+python = "^3.10.0"
 python-dateutil = "2.9.0.post0"
 jsonschema = { version = "4.23.0", extras = ["format"] }
 docstring-parser = "^0.16"
@@ -70,6 +70,7 @@ upload_to_release = false
 build_command = "pip install poetry && poetry build"
 
 [tool.mypy]
+python_version = "3.10"
 packages = "cdxev"
 # Excludes tests even when mypy is invoked with a path (as the VS Code extension does, for instance)
 exclude = ['tests/']