[Bugfix] textproc/meld needs gtksourceview4

Hello,

quick fix for textproc/meld. It refuses to start without gtksourceview4.
No other changes.

Cheers,
Stefan

Index: textproc/meld/Makefile
===================================================================
RCS file: /cvs/ports/textproc/meld/Makefile,v
retrieving revision 1.69
diff -u -p -u -p -r1.69 Makefile
--- textproc/meld/Makefile 19 Apr 2020 07:26:24 -0000 1.69
+++ textproc/meld/Makefile 27 May 2020 18:29:28 -0000
@@ -5,6 +5,7 @@ COMMENT= graphical diff and merge tool
GNOME_VERSION= 3.21.0
GNOME_PROJECT= meld
MODPY_EGG_VERSION= ${GNOME_VERSION}
+REVISION= 0

CATEGORIES= textproc

@@ -25,7 +26,7 @@ MODGNOME_TOOLS= desktop-file-utils gtk-
MODPY_ADJ_FILES= bin/meld

RUN_DEPENDS= devel/py-gobject3${MODPY_FLAVOR} \
- x11/gtksourceview3
+ x11/gtksourceview4

# org.gnome.desktop.interface
RUN_DEPENDS += devel/gsettings-desktop-schemas