refactor the hardcoded constant and close opened file (#57)

there are some constant that are hardcoded into the code before in this commit those are at the top of the file for better code readability and there is a opened file that didn't close before in this commit that is closed

setup.py

@@ -1,10 +1,15 @@
 from setuptools import setup, find_packages
 from os import path
-
+AUTHOR = 'Jina AI'
+AUTHOR_EMAIL = 'hello@jina.ai'
+LICENSE = 'Apache 2.0'
+GITHUB_URL = 'https://github.com/jina-ai/vectordb/'
+DOWNLOAD_URL = 'https://github.com/jina-ai/vectordb/tags'
 try:
     pkg_name = 'vectordb'
     libinfo_py = path.join(pkg_name, '__init__.py')
-    libinfo_content = open(libinfo_py, 'r', encoding='utf-8').readlines()
+    with open(libinfo_py, 'r', encoding='utf-8') as f:
+        libinfo_content = f.readlines()
     version_line = [l.strip() for l in libinfo_content if l.startswith('__version__')][
         0
     ]
@@ -29,11 +34,11 @@
     description='The Python VectorDB. Build your vector database from working as a library to scaling as a database in the cloud',
     long_description=_long_description,
     long_description_content_type='text/markdown',
-    author='Jina AI',
-    author_email='hello@jina.ai',
-    license='Apache 2.0',
-    url='https://github.com/jina-ai/vectordb/',
-    download_url='https://github.com/jina-ai/vectordb/tags',
+    author= AUTHOR,
+    author_email=AUTHOR_EMAIL,
+    license=LICENSE,
+    url=GITHUB_URL,
+    download_url=DOWNLOAD_URL,
     packages=find_packages(),
     classifiers=[
         'Development Status :: 5 - Production/Stable',