docs: remove 3.4 from supported versions list (googleapis#549)

Remove 3.4 from the supported versions list. We no longer actively test it and it has been EOL since March. https://www.python.org/downloads/release/python-3410/

Author: busunkim96

README.rst

@@ -24,7 +24,7 @@ For more information on setting up your Python development environment, please r
 
 Supported Python Versions
 ^^^^^^^^^^^^^^^^^^^^^^^^^
-Python >= 3.4
+Python >= 3.5
 
 Deprecated Python Versions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^

setup.py

@@ -52,7 +52,6 @@
         "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 2.7",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.4",
         "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",