Enforce tensorboard minimum version as 1.15 (#35952)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/34028
Pull Request resolved: https://github.com/pytorch/pytorch/pull/35952
Differential Revision: D20870095
Pulled By: sanekmelnikov
fbshipit-source-id: f7de26a538841d832df3179f49dfa2145e98fcdc
