graphics/librsvg2-rust: force rebuild the package

from pkg 2.0.0 to pkg 2.0.3, a regression made the package "not
providing" librsvg2.so.2 which made pkg trying to install both librsvg2
and librsvg2-rust librsvg2 to satisfy the librsvg2.so.2 shlib dependency
librsvg2-rust to satisfy the direct dependency, resulting in an
unsolvable problem.

PR: 284307