fix: close session after done (#219)

* fix: close session after done

* missing await

Author: firstof9

openevsehttp/__main__.py

@@ -138,6 +138,7 @@ async def process_request(
                 _LOGGER.error("%s", err)
                 message = {"msg": err}
 
+            await session.close()
             return message
 
     async def send_command(self, command: str) -> tuple: