update to TF2, uproot4, etc.
@ExcitingSquid @yongbinfeng I'm trying to update the code to TF2, uproot4, etc. and make a clean environment for people to start from.
Still kind of a work in progress, but let me know what you think.
Also, we should try to centralize developments for L1 MET training + hls4ml conversion into 1 repo. I'm fine if it's this one or Yongbin's (https://github.com/yongbinfeng/DeepMETTraining/tree/l1met), but we should have a main repo that everyone can start from without getting too confused.