I say, and with God's help: All months are days of God Almighty, so there is no objection to congratulating on any of them, especially if people are accustomed to that. However, this hadith is not authentically attributed to the Prophet, peace be upon him, and it is forbidden to lie in fabricating hadiths to encourage people in religion. A Muslim should not convey a message before verifying the accuracy of its content, and God knows best.