update documentation per latest version

examples/mp_api.py

@@ -1,7 +1,11 @@
 """Simple script illustrating some of the features of this package."""
 from pprint import pprint
 
-from marketplace.app.marketplace_app import MarketPlaceApp
+from fastapi.responses import HTMLResponse
+
+from marketplace.app import get_app
+from marketplace.app.v0 import MarketPlaceApp
+from marketplace.app.v0_0_1 import MarketPlaceApp as MarketPlaceApp_v_0_0_1
 from marketplace.client import MarketPlaceClient
 
 # General MarketPlaceClient for simple requests like user info
@@ -13,16 +17,27 @@
 
 
 # To simply instantiate a MarketPlaceApp with a client id
-mp = MarketPlaceApp(client_id="<application_client_id>")
+mp = get_app(app_id="<application_client_id>")
 print(mp.heartbeat())
 
 
 # To extend the MarketPlaceApp with custom implementations
 class MyMarketPlaceApp(MarketPlaceApp):
-    def heartbeat(self) -> str:
+    def heartbeat(self) -> HTMLResponse:
         res = super().heartbeat()
         return f"heartbeat response: {res}"
 
 
-my_mp_app = MyMarketPlaceApp(client_id="<application_client_id>")
+my_mp_app = MyMarketPlaceApp(app_id="<application_client_id>")
 print(my_mp_app.heartbeat())
+
+
+# To extend the MarketPlaceApp with custom implementations for deprecated api version 0.0.1
+class MyMarketPlaceApp_v_0_0_1(MarketPlaceApp_v_0_0_1):
+    def heartbeat(self) -> str:
+        res = super().heartbeat()
+        return f"heartbeat response: {res}"
+
+
+my_mp_app_v_0_0_1 = MyMarketPlaceApp_v_0_0_1(client_id="<application_client_id>")
+print(my_mp_app_v_0_0_1.heartbeat())