`dlopen_derive` is unmaintained

dlopenderive hasn't been updated since June 9, 2019. dlopenderive depends on quote = "0.6.12" and syn = "0.15.34". Versions 1.0.0 of these dependencies were published on August 13, 2019. The 0. versions haven't received updates since. Note that dlopen is an unmaintained crate from the same...