Feature request: Support for lowercase file name

[antonkesy]

By convention Makefiles-files are written with an uppercase M, but I've seen (and work on) projects which use makefile; which this plugin does not recognize :(

Would it be possible to add the detection of those files too? Please 🥺

Thank you for this great plugin ❤️

[Zeioth]

@antonkesy sorry for not noticing this one before. Issue accepted. We are gonna suport all common conventions for Makefile filename on the next version.