Removing old deprecation warning and adding requirement of python >= 3.7 in setup.py

Author: swansonk14

setup.py

@@ -1,11 +1,9 @@
-import os
+from pathlib import Path
 from setuptools import find_packages, setup
 
 # Load version number
-__version__ = None
-
-src_dir = os.path.abspath(os.path.dirname(__file__))
-version_file = os.path.join(src_dir, 'tap', '_version.py')
+__version__ = ''
+version_file = Path(__file__).parent.absolute() / 'tap' / '_version.py'
 
 with open(version_file) as fd:
     exec(fd.read())
@@ -33,6 +31,7 @@
         'docstring-parser >= 0.15'
     ],
     tests_require=['pytest'],
+    python_requires='>=3.7',
     classifiers=[
         'Programming Language :: Python :: 3',
         'Programming Language :: Python :: 3.7',

tap/tap.py

@@ -303,13 +303,6 @@ def _add_arguments(self) -> None:
             if variable not in self.class_variables:
                 self._add_argument(*name_or_flags, **kwargs)
 
-    def add_arguments(self) -> None:
-        """Deprecated and will be removed by January 1st, 2021.
-
-        Explicitly add arguments to the argument buffer if not using default settings.
-        """
-        pass
-
     def process_args(self) -> None:
         """Perform additional argument processing and/or validation."""
         pass