pubsub: standardize publish delay threshold and max extension

As an effort to standardize client library defaults across languages
for Pub/Sub, we're making the following changes:
DefaultReceiveSettings.MaxExtension:   10min -> 60min
DefalutPublishSettings.DelayThreshold: 1ms -> 10ms

These changes should not have an adverse effect
on users as they have been the default for the Java
and Python client libraries for a while now.

Change-Id: I5a0a940f97bb68dee2f893e55dbfc56966d7cc93
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/49992
Reviewed-by: Cody Oss <codyoss@google.com>
Reviewed-by: kokoro <noreply+kokoro@google.com>
diff --git a/pubsub/subscription.go b/pubsub/subscription.go
index c9f1480..c7239e7 100644
--- a/pubsub/subscription.go
+++ b/pubsub/subscription.go
@@ -374,7 +374,7 @@
 
 // DefaultReceiveSettings holds the default values for ReceiveSettings.
 var DefaultReceiveSettings = ReceiveSettings{
-	MaxExtension:           10 * time.Minute,
+	MaxExtension:           60 * time.Minute,
 	MaxExtensionPeriod:     -1,
 	MaxOutstandingMessages: 1000,
 	MaxOutstandingBytes:    1e9, // 1G
diff --git a/pubsub/topic.go b/pubsub/topic.go
index e03e227..cf8fc5d 100644
--- a/pubsub/topic.go
+++ b/pubsub/topic.go
@@ -97,7 +97,7 @@
 
 // DefaultPublishSettings holds the default values for topics' PublishSettings.
 var DefaultPublishSettings = PublishSettings{
-	DelayThreshold: 1 * time.Millisecond,
+	DelayThreshold: 10 * time.Millisecond,
 	CountThreshold: 100,
 	ByteThreshold:  1e6,
 	Timeout:        60 * time.Second,