updated struct to PortSpec

docs/changelog.md

 # TBD
 
+### Breaking changes
+- Updated `struct` to `PortSpec` for declaring port definitions
+
 # 0.0.5
 
 ### Fixes

src/shared_utils/shared_utils.star

@@ -25,4 +25,4 @@ def path_dir(path):
 
 
 def new_port_spec(number, protocol):
-	return struct(number = number, protocol = protocol)
+	return PortSpec(number = number, protocol = protocol)