Adding centralized version for the tool.

Version of the tool is hard coded in setup.py which
means that it'll have to specially declared as a
var everywhere you would need it. Hence adding file
version.py under pybadges directory and adding code
to fetch in in setup.py and __main__.py

Signed-off-by: kshithijiyer <kshithij.ki@gmail.com>

Author: kshithijiyer

pybadges/__init__.py

@@ -36,6 +36,7 @@
 from typing import Optional
 import urllib.parse
 from xml.dom import minidom
+from version import __version__
 
 import jinja2
 import requests

pybadges/__main__.py

@@ -22,8 +22,8 @@
 import sys
 import tempfile
 import webbrowser
-
 import pybadges
+from version import __version__
 
 
 def main():
@@ -107,7 +107,10 @@ def main():
         default=None,
         help='the title to associate with the right part of the badge. See '
              'https://developer.mozilla.org/en-US/docs/Web/SVG/Element/title')
-
+    parser.add_argument(
+        '-v', '--version',
+        action='version',
+        version='%(prog)s {version}'.format(version=__version__))
     args = parser.parse_args()
 
     if (args.left_link or args.right_link) and args.whole_link:

pybadges/version.py

@@ -0,0 +1,14 @@
+# Copyright 2019 The pybadge Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+__version__='2.2.0'

setup.py

@@ -18,7 +18,7 @@
 import re
 
 from setuptools import setup
-
+from distutils2 import get_version
 
 def get_long_description():
     """Transform README.md into a usable long description.
@@ -41,7 +41,7 @@ def replace_relative_with_absolute(match):
 
 setup(
     name='pybadges',
-    version='2.2.0',
+    version= get_version('pybadges/version.py'),
     author='Brian Quinlan',
     author_email='brian@sweetapp.com',
     classifiers=[