boinc: remove unused webkit2gtk makedep

It was used to append it to ldflags but not anymore.

srcpkgs/boinc/template

@@ -7,7 +7,7 @@ build_style=gnu-configure
 hostmakedepends="automake libtool pkg-config xorgproto shared-mime-info"
 makedepends="glu-devel libfreeglut-devel libcurl-devel
  libjpeg-turbo-devel libnotify-devel sqlite-devel libxcb-devel
- libXmu-devel libXi-devel webkit2gtk-devel wxWidgets-gtk3-devel"
+ libXmu-devel libXi-devel wxWidgets-gtk3-devel"
 depends="curl ca-certificates"
 conf_files="/etc/default/boinc-client"
 short_desc="Berkely Infrastructure for Network Computing"