fix: use correct separator

See https://github.com/nvim-neotest/neotest/issues/118

lua/neotest-python/init.lua

@@ -5,7 +5,7 @@ local base = require("neotest-python.base")
 
 local function script_path()
   local str = debug.getinfo(2, "S").source:sub(2)
-  return str:match("(.*/)")
+  return str:match(("(.*%s)"):format(lib.files.sep))
 end
 
 local python_script = (Path.new(script_path()):parent():parent() / "neotest.py").filename