Use conditional requirements for google-api-core.

PiperOrigin-RevId: 369500403
Change-Id: I0eca3f902a45b8b8ef1f8648f0c7e6797bdef6b0

Author: mctavish

src/setup.py

@@ -23,7 +23,6 @@
 from glob import glob
 import os
 import re
-import sys
 from distutils import sysconfig
 from setuptools import Extension
 from setuptools import setup
@@ -113,8 +112,8 @@ def ReadConfig(section, value, default):
         'google-auth==1.8.2; python_version < "3.0"',
         'google-auth>=1.0.0; python_version > "3.0"',
         'google-auth-httplib2',
-        'google-api-core==1.15.0'
-        if sys.version_info.major < 3 else 'google-api-core',
+        'google-api-core==1.15.0; python_version < "3.0"',
+        'google-api-core; python_version > "3.0"',
         'pyyaml',
         'six>=1.10.0',
     ],