fix paste from clipboard (ctrl+shift+y)

from Joshua Lloret on the ML:

"attached is a small patch to enable pasting from clipboard, as well as primary.

It seems like there was already code in there to allow this, but since there was never any case to match the upper case 'Y', that inline if would always evaluate to false."

dmenu.c

@@ -320,6 +320,7 @@ keypress(XKeyEvent *ev)
 				insert(NULL, nextrune(-1) - cursor);
 			break;
 		case XK_y: /* paste selection */
+		case XK_Y:
 			XConvertSelection(dpy, (ev->state & ShiftMask) ? clip : XA_PRIMARY,
 			                  utf8, utf8, win, CurrentTime);
 			return;