README.md: Add trailing newline

In part because POSIX defines a text file as having a trailing
newline
https://stackoverflow.com/questions/729692/why-should-text-files-end-with-a-newline
but also because every time I edit this file with my favorite text
editor (vim), it insists on adding the final newline itself, so I
have to repeatedly un-add it manually which is irritating.

README.md

@@ -47,4 +47,4 @@ Original author unknown. Reverse-engineered and maintained by Michael Steil, mis
 
 ## Contributing
 
-Contributions to this project are very welcome.
+Contributions to this project are very welcome.