Pin google-auth >= 1.1.0. (#3950)

Author: tseaver

packages/google-cloud-spanner/setup.py

@@ -52,6 +52,7 @@
 
 REQUIREMENTS = [
     'google-cloud-core >= 0.27.0, < 0.28dev',
+    'google-auth >= 1.1.0',
     'grpcio >= 1.2.0, < 2.0dev',
     'gapic-google-cloud-spanner-v1 >= 0.15.0, < 0.16dev',
     'gapic-google-cloud-spanner-admin-database-v1 >= 0.15.0, < 0.16dev',