PBS: added endpoint-compression config (#3828)

prebid-server/developers/add-new-bidder-java.md

@@ -83,6 +83,7 @@ Create a file with the path `static/bidder-info/{bidder}.yaml` and begin with th
 adapters:
   yourBidderCode:
     endpoint: http://possible.endpoint
+    endpoint-compression: gzip (or none)
     meta-info:
       maintainer-email: [email protected]
       app-media-types:
@@ -112,6 +113,7 @@ Modify this template for your bid adapter:
 - Change the `vendor-id` value to id of your bidding server as registered with the [GDPR Global Vendor List (GVL)](https://iabeurope.eu/vendor-list-tcf-v2-0/). Leave this as `0` if you are not registered with IAB Europe.
 - Choose the `supported-vendors` constants: These constants should be unique. The list of existing vendor constants can be found [here](https://github.com/prebid/prebid-server-java/blob/master/src/main/java/org/prebid/server/bidder/ViewabilityVendors.java).
 - Remove the `capabilities` (app/site) and `mediaTypes` (banner/video/audio/native) combinations which your adapter does not support.
+- If your auction endpoint supports gzip compression, setting 'endpoint-compression' to 'gzip' will save on network fees.
 - Change the `cookie-family-name` to the name which will be used for storing your user sync id within the federated cookie. Please keep this the same as your bidder name.
   If you implemented a user syncer, you'll need to provide a default endpoint.
   The user sync endpoint is composed of two main parts, the url of your user syncer and a redirect back(redirect-url) to Prebid Server. The url of your user syncer is responsible for reading the user id from the client's cookie and redirecting to Prebid Server with a user id macro resolved.