Remove unused run time dependency on utfcpp.

https://github.com/osmcode/libosmium/commit/68c981313572e960e96d417f42a086d8a2213bff


Index: Makefile
===================================================================
RCS file: /cvs/ports/geo/libosmium/Makefile,v
retrieving revision 1.9
diff -u -p -u -p -r1.9 Makefile
--- Makefile	24 Nov 2023 08:50:40 -0000	1.9
+++ Makefile	23 Mar 2024 22:12:10 -0000
@@ -3,6 +3,7 @@ COMMENT =	fast, flexible library for wor
 GH_ACCOUNT =	osmcode
 GH_PROJECT =	libosmium
 GH_TAGNAME =	v2.20.0
+REVISION =	0
 
 CATEGORIES =	geo
 
@@ -20,9 +21,5 @@ BUILD_DEPENDS =	devel/boost \
 		devel/sparsehash \
 		geo/gdal \
 		geo/geos
-
-# include/osmium/io/detail/opl_parser_functions.hpp
-# #include <utf8.h>
-RUN_DEPENDS =	devel/utfcpp
 
 .include <bsd.port.mk>