Fix API docs for mercure version

docs/swagger/definitions/MercureInfo.json

@@ -16,7 +16,7 @@
         },
         "version": {
             "type": "string",
-            "enum": ["v0", "v1"],
+            "enum": ["legacy", "stable"],
             "description": "Indicates the version of the mercure hub that has been configured, so that consumers know how to subscribe"
         }
     }

docs/swagger/paths/v2_mercure-info.json

@@ -28,7 +28,7 @@
                             "mercureHubUrl": "https://example.com/.well-known/mercure",
                             "jwt": "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJTaGxpbmsiLCJpYXQiOjE1ODY2ODY3MzIsImV4cCI6MTU4Njk0NTkzMiwibWVyY3VyZSI6eyJzdWJzY3JpYmUiOltdfX0.P-519lgU7dFz0bbNlRG1CXyqugGbaHon4kw6fu4QBdQ",
                             "jwtExpiration":  "2020-04-15T12:18:52+02:00",
-                            "version": "v1"
+                            "version": "stable"
                         }
                     }
                 }