Add gobject-introspection to build requires to ensure typelibs
are pulled in on install.

Run spec-cleaner.

before fix;
[ 35s] Provides: application() application(macrofusion.desktop) macrofusion = 0.7.4-lp152.14.1 mimehandler(application/x-mfusion) mimehandler(image/jpeg) mimehandler(image/tiff)
[ 35s] Requires(rpmlib): rpmlib(CompressedFileNames) <= 3.0.4-1 rpmlib(FileDigests) <= 4.6.0-1 rpmlib(PayloadFilesHavePrefix) <= 4.0-1
[ 35s] Requires: /usr/bin/python3

after fix;
[ 24s] Provides: application() application(macrofusion.desktop) macrofusion = 0.7.4-0 mimehandler(application/x-mfusion) mimehandler(image/jpeg) mimehandler(image/tiff)
[ 24s] Requires(rpmlib): rpmlib(CompressedFileNames) <= 3.0.4-1 rpmlib(FileDigests) <= 4.6.0-1 rpmlib(PayloadFilesHavePrefix) <= 4.0-1
[ 24s] Requires: /usr/bin/python3 typelib(GExiv2) typelib(GObject) typelib(Gdk) typelib(GdkPixbuf) typelib(Gtk)