Display exception name when subprocesses raise them

This change provides more context information for cases like when
a command is not found as previous behavior only returned the exist
code of the exception, without any other information. Same exit codes
could have being produced by commands that did run.

Author: ssbarnea

src/tox/execute/local_sub_process/__init__.py

@@ -214,6 +214,9 @@ def __enter__(self) -> ExecuteStatus:
                 env=self.request.env,
             )
         except OSError as exception:
+            # We log a nice error message to avout returning opaque error codes,
+            # like exit code 2 (filenotfound).
+            logging.error("Exception running subprocess %s", str(exception))  # noqa: TRY400
             return LocalSubprocessExecuteFailedStatus(self.options, self._out, self._err, exception.errno)
 
         status = LocalSubprocessExecuteStatus(self.options, self._out, self._err, process)