Added info on semantic versioning and branching strategy to CONTRIBUTING.md

Also:
- Added isort to Pipenv dev
- Added setup.cfg to make it easy to run flake8, doc8, and isort directly from the command line without using invoke
- Ran isort to sort includes

1 files changed, 10 insertions, 4 deletions

diff --git a/cmd2/argparse_completer.py b/cmd2/argparse_completer.py
index f61f5fd8..61f173cc 100644
--- a/cmd2/argparse_completer.py
+++ b/cmd2/argparse_completer.py
@@ -14,10 +14,16 @@ from collections import deque
 from typing import Dict, List, Optional, Union
 
 from . import ansi, cmd2, constants
-from .argparse_custom import ATTR_CHOICES_CALLABLE, generate_range_error
-from .argparse_custom import ATTR_SUPPRESS_TAB_HINT, ATTR_DESCRIPTIVE_COMPLETION_HEADER, ATTR_NARGS_RANGE
-from .argparse_custom import ChoicesCallable, CompletionItem
-from .utils import basic_complete, CompletionError
+from .argparse_custom import (
+    ATTR_CHOICES_CALLABLE,
+    ATTR_DESCRIPTIVE_COMPLETION_HEADER,
+    ATTR_NARGS_RANGE,
+    ATTR_SUPPRESS_TAB_HINT,
+    ChoicesCallable,
+    CompletionItem,
+    generate_range_error,
+)
+from .utils import CompletionError, basic_complete
 
 # If no descriptive header is supplied, then this will be used instead
 DEFAULT_DESCRIPTIVE_HEADER = 'Description'