Add plugin flake8-type-checking (#18)

Author: tothtamas28

{{cookiecutter.project_slug}}/.flake8

@@ -1,6 +1,7 @@
 [flake8]
 max-line-length = 120
-extend-select = B9
+extend-select = B9, TC1
 extend-ignore = B950,E,W1,W2,W3,W4,W5
 per-file-ignores =
     */__init__.py: F401
+type-checking-strict = true

{{cookiecutter.project_slug}}/pyproject.toml

@@ -20,6 +20,7 @@ flake8 = "*"
 flake8-bugbear = "*"
 flake8-comprehensions = "*"
 flake8-quotes = "*"
+flake8-type-checking = "*"
 isort = "*"
 mypy = "*"
 pep8-naming = "*"