Update tensorflow version to 1.14.0rc0

Signed-off-by: Yong Tang <[email protected]>

Author: yongtang

setup.py

@@ -95,7 +95,7 @@ def has_ext_modules(self):
 """
 
 # Note: Change to tensorflow == 1.13.0 once 1.13.0 is released
-package = 'tensorflow>=1.13.0,<1.14.0'
+package = 'tensorflow==1.14.0rc0'
 version = '0.6.0'
 project = 'tensorflow-io'
 if '--package-version' in sys.argv: