[SECURITY] Fedora 33 Update: libproxy-0.4.15-25.fc33

libproxy offers the following features: * extremely small core footprint (< 35K) * no external dependencies within libproxy core (libproxy plugins may have dependencies) * only 3 functions in the stable external API * dynamic adjustment to changing network topology * a standard way of dealing with proxy settings across all scenarios * a sublime sense of joy and accomplishment