Bump NQP to get new "-" behaviour

When you start Raku with "-" as a single positional parameter, it
will now check if STDIN is connected to a terminal.  If it is, then
the REPL will be started, rather than appearing to freeze waiting
for the user to enter something and issue an EOF.  If STDIN is *not*
connected to a terminal, then Raku will read from STDIN and process
that as the source of a program.

tools/templates/NQP_REVISION

@@ -1 +1 @@
-2020.05-43-g79fb9251e
+2020.05-46-g59c6124d0