Update README.md operational server (#1137)

## Motivation

After following the README I had issues setting up the operational
webhooks locally, this was due to the README suggesting that the setting
`operational_webhook_address` is commonly set to
`http://127.0.0.1:8071/`

See following discussion for more details:
[#1125

## Solution

The setting should be `http://127.0.0.1:8071` so this PR is just
updating the README.

Author: boothj5

README.md

@@ -292,7 +292,7 @@ Operational webhooks are webhooks that you can subscribe to in order to get noti
 
 The operational webhooks utilize Svix, and are controlled by a special account service account with the following ID: `org_00000000000SvixManagement00`.
 
-The first step is to turn it on by setting the `operational_webhook_address` config to point to your Svix server. The most common value for this setting is `http://127.0.0.1:8071/`, though it may be different based on your specific setup.
+The first step is to turn it on by setting the `operational_webhook_address` config to point to your Svix server. The most common value for this setting is `http://127.0.0.1:8071`, though it may be different based on your specific setup.
 
 The above step enables operational webhooks on this instance, and the next step is to enable it for your specific organization. As mentioned above, operational webhooks use a normal Svix account behind the scenes, so we'll first need to get the authentication token for this account. To do this you should run: