fix: sh retcode from the last real build plan shell command

Author: ahlinc

package.py

@@ -943,7 +943,15 @@ def execute(self, build_plan, zip_stream, query):
                 with tempfile.NamedTemporaryFile(mode="w+t", delete=True) as temp_file:
                     path, script = action[1:]
                     # NOTE: Execute `pwd` to determine the subprocess shell's working directory after having executed all other commands.
-                    script = f"{script}\npwd >{temp_file.name}"
+                    script = "\n".join(
+                        (
+                            script,
+                            "retcode=$?",
+                            f"pwd >{temp_file.name}",
+                            "exit $retcode",
+                        )
+                    )
+
                     p = subprocess.Popen(
                         script,
                         shell=True,