Fix git diff with empty line at the end of the git diff will cause corrupt diff apply message

trains_agent/helper/repo.py

@@ -382,7 +382,8 @@ class VCS(object):
         Run command with `input_` as stdin
         """
         input_ = input_.encode("utf-8")
-        if not input_.endswith(b"\n"):
+        # always add extra empty line 
+        # (there is no downside, and it solves empty lines issue at end of patch cause corrupt message)
         input_ += b"\n"
         process = self._call_subprocess(
             subprocess.Popen,