use Popen context manager for periodic update process (#2472)

Author: sigma67

docs/changelog/2472.bugfix.rst

@@ -0,0 +1 @@
+Use Popen context manager for periodic update process to prevent ResourceWarning due to unclosed files

src/virtualenv/seed/wheels/periodic_update.py

@@ -220,7 +220,7 @@ def trigger_update(distribution, for_py_version, wheel, search_dirs, app_data, e
     kwargs = {"stdout": pipe, "stderr": pipe}
     if not debug and sys.platform == "win32":
         kwargs["creationflags"] = CREATE_NO_WINDOW
-    process = Popen(cmd, **kwargs)  # noqa: S603
+    process = Popen(cmd, close_fds=True, **kwargs)  # noqa: S603
     logging.info(
         "triggered periodic upgrade of %s%s (for python %s) via background process having PID %d",
         distribution,