Seggregate versionning to a separate variable

Add `__version__` string to `version.py`.
Now, running `playx --version` gives a version.

playx/__init__.py

@@ -1,3 +1,5 @@
+from .version import __version__
+
 name = "playx"
 
 __all__ = [

playx/main.py

@@ -6,6 +6,7 @@
 
 import argparse
 
+from .version import __version__
 from playx.logger import Logger
 
 from playx.cache import Cache, clean_url_cache
@@ -31,6 +32,7 @@ def parse():
                                      the github\
                                      (https://github.com/NISH1001/playx) page"
     )
+    parser.add_argument("--version", action="version", version=__version__)
     parser.add_argument(
         "song",
         help="Name or youtube link of song to download",

playx/version.py

@@ -0,0 +1 @@
+__version__ = "1.5.2"

setup.py

@@ -1,5 +1,7 @@
 from setuptools import setup
 
+exec(open("playx/version.py").read())
+
 setup(
     name="playx",
     packages=["playx", "playx.playlist"],
@@ -9,7 +11,7 @@
     long_description="Search and play any song from terminal seamlessly.",
     url="http://github.com/NISH1001/playx",
     entry_points={"console_scripts": ["playx = playx.main:main"]},
-    version="1.5.2",
+    version=__version__,
     license="MIT",
     install_requires=["youtube_dl", "requests", "beautifulsoup4", "selenium", "lxml",],
 )