Bid adapter PGAMSSP: new adapter (#4810)

* new adapter PGAMSSP

* upd

dev-docs/bidders/pgamssp.md

@@ -0,0 +1,30 @@
+---
+layout: bidder
+title: PGAMSSP
+description: Prebid PGAMSSP Bidder Adapter
+biddercode: pgamssp
+usp_supported: true
+tcfeu_supported: false
+coppa_supported: true
+schain_supported: true
+floors_supported: true
+media_types: banner, video, native
+pbjs: true
+pbs: true
+pbs_app_supported: true
+sidebarType: 1
+multiformat_supported: will-bid-on-one
+safeframes_ok: true
+---
+
+### Bid Params
+
+{: .table .table-bordered .table-striped }
+| Name          | Scope    | Description           | Example   | Type      |
+|---------------|----------|-----------------------|-----------|-----------|
+| `placementId`      | optional | Placement Id         | `'0'`    | `'string'` |
+| `endpointId`      | optional | Endpoint Id         | `'0'`    | `'string'` |
+
+### Note
+
+For the prebid server and prebid.js you only need to use one parameter: either placementId or endpointId