Handle backslash escaping in Windows for path regex.

pre_commit/languages/lua.py

@@ -66,7 +66,8 @@ def _get_lua_path_version(
     # This could sniff out from _VERSION, but checking package.path should
     # provide an answer for *exactly* where lua is looking for packages.
     _, stdout, _ = cmd_output(lua_executable, '-e', 'print(package.path)')
-    match = re.search(fr'{os.sep}lua{os.sep}(.*?){os.sep}', stdout)
+    sep = os.sep if os.name != 'nt' else os.sep * 2
+    match = re.search(fr'{sep}lua{sep}(.*?){sep}', stdout)
     if match:
         return match[1]