Release v1.6.0 (#324)

* Update version and changelog for v1.6.0
* Update docs
diff --git a/docs/dyn/sqladmin_v1beta3.tiers.html b/docs/dyn/sqladmin_v1beta3.tiers.html
index d58123b..70bcf3b 100644
--- a/docs/dyn/sqladmin_v1beta3.tiers.html
+++ b/docs/dyn/sqladmin_v1beta3.tiers.html
@@ -95,7 +95,7 @@
         "tier": "A String", # An identifier for the service tier, for example D1, D2 etc. For related information, see Pricing.
         "kind": "sql#tier", # This is always sql#tier.
         "RAM": "A String", # The maximum RAM usage of this tier in bytes.
-        "region": [ # The applicable regions for this tier. Can be us-east1, europe-west1, or asia-east1.
+        "region": [ # The applicable regions for this tier.
           "A String",
         ],
       },