Add pytest, doc8, and mypy config back to setup.cfg

setup.cfg

@@ -0,0 +1,26 @@
+[tool:pytest]
+testpaths =
+    tests
+addopts =
+    --cov=cmd2
+    --cov-append
+    --cov-report=term
+    --cov-report=html
+
+[doc8]
+ignore-path=docs/_build,.git,.idea,.pytest_cache,.tox,.nox,.venv,.vscode,build,cmd2,examples,tests,cmd2.egg-info,dist,htmlcov,__pycache__,*.egg,plugins
+max-line-length=120
+verbose=0
+
+[mypy]
+disallow_incomplete_defs = True
+disallow_untyped_defs = True
+disallow_untyped_calls = True
+warn_redundant_casts = True
+warn_unused_ignores = False
+warn_return_any = True
+warn_unreachable = True
+strict = True
+show_error_context = True
+show_column_numbers = True
+show_error_codes = True