fix(compose): return type in get_service_port docstring (#939)

Noticed a mismatch in a function docstring while using the library.
Fixed return type of `get_service_port` from `str` to `int`

Co-authored-by: Roy Moore <roy@moore.co.il>

Author: PraneethJain

core/testcontainers/compose/compose.py

@@ -506,7 +506,7 @@ def get_service_port(
 
         Returns
         -------
-        str:
+        int:
             The mapped port on the host
         """
         normalize: PublishedPortModel = self.get_container(service_name).get_publisher(by_port=port).normalize()