session: update swagger yaml

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

api/swagger.yaml

@@ -8481,3 +8481,43 @@ paths:
           type: "string"
           required: true
       tags: ["Distribution"]
+  /session:
+    post:
+      summary: "Initialize interactive session"
+      description: |
+        Start a new interactive session with a server. Session allows server to call back to the client for advanced capabilities.
+
+        ### Hijacking
+
+        This endpoint hijacks the HTTP connection to HTTP2 transport that allows the client to expose gPRC services on that connection.
+
+        For example, the client sends this request to upgrade the connection:
+
+        ```
+        POST /session HTTP/1.1
+        Upgrade: h2c
+        Connection: Upgrade
+        ```
+
+        The Docker daemon will respond with a `101 UPGRADED` response follow with the raw stream:
+
+        ```
+        HTTP/1.1 101 UPGRADED
+        Connection: Upgrade
+        Upgrade: h2c
+        ```
+      operationId: "Session"
+      produces:
+        - "application/vnd.docker.raw-stream"
+      responses:
+        101:
+          description: "no error, hijacking successful"
+        400:
+          description: "bad parameter"
+          schema:
+            $ref: "#/definitions/ErrorResponse"
+        500:
+          description: "server error"
+          schema:
+            $ref: "#/definitions/ErrorResponse"
+      tags: ["Session"]